- Production and Application of Highly Efficient and Reusable Palladium Nanocatalyst Decorated on the Magnetically Retrievable Chitosan/Activated Carbon Composite Microcapsules
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Abstract: This study reports (i) the production of magnetically retrievable microcapsules as immobilizing agents, which are composed of chitosan/activated carbon composite (CS-AC/Fe3O4), (ii) the green synthesis of highly stable palladium nanoparticles on CS-AC/Fe3O4 without using any toxic reducing agents (Pd NPs@CS-AC/Fe3O4), (iii) the investigation of catalytic behavior of Pd NPs@CS-AC/Fe3O4 in Suzuki–Miyaura reactions of different aryl iodides, bromides, and chlorides, and (iv) the examination of recoverability and reusability of Pd NPs@CS-AC/Fe3O4. The characterization of Pd NPs@CS-AC/Fe3O4 was performed by FT-IR, TG/DTG, XRD, SEM, and EDS analyses. It was found that the average sizes of palladium nanoparticles were changed in the range of 31–48?nm. The catalytic tests revealed that Pd NPs@CS-AC/Fe3O4 was a very effective catalyst against synthesis of various biaryl compounds via Suzuki–Miyaura reactions, by giving high reaction yields under mild reaction conditions. Furthermore, it was found that Pd NPs@CS-AC/Fe3O4 was a highly retrievable and practical nanocatalyst due to its reusable nature. Pd NPs@CS-AC/Fe3O4 gave 95% of yield after ten successive cycles. These results show that Pd NPs@CS-AC/Fe3O4 is a superb catalyst and it can be applied in different catalytic systems or industrial applications due to the fact that it offers notable advantages such as high catalytic performance, reusability, stability, excellent functional group tolerance, wide substrate scope, and simple separation. Graphical Abstract: [Figure not available: see fulltext.].
- Baran, Talat
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- Synthesis, characterization, and catalytic activity in Suzuki coupling and catalase-like reactions of new chitosan supported Pd catalyst
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The aim of this study is to analyze the synthesis of a new chitosan supported Pd catalyst and examination of its catalytic activity in: Suzuki coupling reactions by improving a simple, fast, and solvent-free microwave method.H2O2 decomposition reaction to find out its redox potential. Pd catalyst was synthesized using chitosan as a biomaterial and characterized with FTIR, TG/DTG, XRD, 1H NMR, 13C NMR, SEM-EDAX, ICP-OES, Uv-vis spectroscopies, and magnetic moment, along with molar conductivity analysis. Biomaterial supported Pd catalyst indicated high activity and long life time as well as excellent turnover number (TON) and turnover frequency (TOF) values in Suzuki reaction. Biomaterial supported Pd catalyst catalyzed H2O2 decomposition reaction with considerable high activity using comparatively small loading catalyst (10 mg). Redox potential of biomaterial supported Pd catalyst was still high without negligible loss (13% decrease) after 10 cycles in reusability tests. As a consequence, eco-friendly biomaterial supported Pd catalyst has superior properties such as high thermal stability, long life time, easy removal from reaction mixture and durability to air, moisture and high temperature.
- Baran, Talat,Inanan, Tülden,Mente?, Ayfer
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- Palladium nanoparticles-decorated triethanolammonium chloride ionic liquid-modified TiO2 nanoparticles (TiO2/IL-Pd): A highly active and recoverable catalyst for Suzuki–Miyaura cross-coupling reaction in aqueous medium
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In this work, an easily obtained procedure was successfully implemented to prepare novel palladium nanoparticles decorated on triethanolammonium chloride ionic liquid-functionalized TiO2 nanoparticles [TiO2/IL-Pd]. Different methods were carried out for characterizations of the synthesized nanocatalyst (HR-TEM, XPS, XRD, FE-SEM, EDX, FT-IR and ICP). TiO2/IL-Pd indicated good catalytic activity for the Suzuki–Miyaura cross-coupling reaction of arylboronic acid with different aryl halides in aqueous media at ambient temperature. The recycled catalyst was investigated with ICP to amount of Pd leaching after 6 times that had diminished slightly, Thus, was confirmed that the nanocatalyst has a good sustainability for C–C Suzuki–Miyaura coupling reaction. The catalyst can be conveniently separated by filtration of the reaction mixture and reused for 6 times without significant loss of its activity. It supplies an environmentally benign alternative path to the existing protocols for the Suzuki–Miyaura reaction.
- Veisi, Hojat,Kamangar, Sheida Ahany,Mohammadi, Pourya,Hemmati, Saba
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- Graphene Oxide Catalyzed C-H Bond Activation: The Importance of Oxygen Functional Groups for Biaryl Construction
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A heterogeneous, inexpensive, and environmentally friendly graphene oxide catalytic system for the C-H bond arylation of benzene enables the formation of biaryl compounds in the presence of aryl iodides. The oxygen functional groups in these graphene oxide sheets and the addition of KOtBu are essential for the observed catalytic activity. Reactions with various model compounds and DFT calculations confirmed that these negatively charged oxygen atoms promote the overall transformation by stabilizing and activating K+ ions, which in turns facilitates the activation of the C-I bond. However, the graphene π system also greatly facilitates the overall reaction as the aromatic coupling partners are easily adsorbed.
- Gao, Yongjun,Tang, Pei,Zhou, Hu,Zhang, Wei,Yang, Hanjun,Yan, Ning,Hu, Gang,Mei, Donghai,Wang, Jianguo,Ma, Ding
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- Sustainable chitosan/starch composite material for stabilization of palladium nanoparticles: Synthesis, characterization and investigation of catalytic behaviour of Pd@chitosan/starch nanocomposite in Suzuki–Miyaura reaction
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We fabricated a green chitosan/starch composite as support material for stabilization of palladium nanoparticles for the first time. The chemical structure of the sustainable palladium nanocomposite was investigated using various techniques. Characterization studies showed that the average dimensions of the palladium nanocomposite ranged between 16 and 21?nm. The synthesized palladium nanocomposite was employed in the synthesis of a series of biphenyl compounds via Suzuki–Miyaura cross-coupling reactions with an unconventional technique. All coupling reactions were conducted in very short reaction time and excellent biphenyl yields were obtained in the presence of the nanocomposite. The palladium catalyst was tolerant to a wide range of functional groups. We also investigated the recyclability and reusability of the palladium nanocomposite, and found that it could be used for seven successive cycles.
- Baran, Talat,Y?lmaz Baran, Nuray,Mente?, Ayfer
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- Visible Light Photoredox Catalyzed Biaryl Synthesis Using Nitrogen Heterocycles as Promoter
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Although transition-metal-catalyzed direct arylation of aromatic C-H bonds is one of the most efficient ways for the construction of biaryl targets, it is also expected for other alternative methods that can use inexpensive catalysts and abundant solar energy to drive chemical reactions. Herein, we describe a new activation mode for biaryl synthesis by using a photosensitive complex of potassium tert-butoxide (KOt-Bu) and nitrogenous heterocyclic ligands via visible light excitation. Under low-energy visible light irradiation, the single-electron transfer from electron-donor KOt-Bu to electron-deficient nitrogenous heterocycle occurred in the inner part of the complex by using potassium as a bridge atom. The ligand accepted the as-photoexcited single electron and transformed into stable radical anions which played a dominant role in the coupling reactions of benzene with aryl halides at ambient temperature. This reaction paradigm features the use of inexpensive catalyst, abundant visible light energy, and more accessible bromobenzene for the construction of biaryl compounds under rather mild conditions. (Figure Presented).
- Xu, Zhen,Gao, Li,Wang, Lele,Gong, Meiwei,Wang, Wenfeng,Yuan, Rusheng
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- Post-synthetic modification of IRMOF-3 with an iminopalladacycle complex and its application as an effective heterogeneous catalyst in Suzuki-Miyaura cross-coupling reaction in H2O/EtOH media at room temperature
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A novel iminopalladacycle complex was successfully immobilized onto a metal–organic framework (MOF) through post-synthetic modification of IRMOF-3. Initially, the IRMOF-3 was modified with benzaldehyde to achieve a Schiff-base moiety in the pores of IRMOF-3 (IRMOF-3-BI) which could anchor the palladium by the addition of palladium acetate (IRMOF-3-BI-Pd). The catalyst was fully characterized by using a variety of methods such as attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), energy dispersive X-ray (EDX), inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). Also, the structural unities of MOFs have been confirmed by scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) analysis. Moreover, the prepared catalyst has exceptionally shown excellent turnover frequencies (up to 300,000) as a heterogonous catalyst in the Suzuki C-C coupling reaction for aryl iodides, bromides and chlorides in H2O/EtOH media at room temperature. Additionally, the catalyst can be easily isolated from the reaction mixture and recycled for five sequential runs without incredible decrease in catalytic efficiency.
- Nouri, Fatemeh,Rostamizadeh, Shahnaz,Azad, Mohammad
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- 1-Phosphabarrelene complexes of palladium and their use in Suzuki-Miyaura coupling reactions
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A bulky 1-phosphabarrelene, 2, was obtained from the reaction of a phosphinine with benzyne; two palladium complexes of 2 were successfully employed in the Suzuki-Miyaura coupling of several aryl chlorides with phenylboronic acid at a relatively low catalyst loading, and activated aryl chlorides were coupled at room temperature in the absence of strong bases. The Royal Society of Chemistry.
- Blug, Matthias,Guibert, Clément,Le Goff, Xavier-Frederic,Mézailles, Nicolas,Le Floch, Pascal
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- Iron/iron oxide nanoparticles: A versatile support for catalytic metals and their application in Suzuki-Miyaura cross-coupling reactions
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Iron/iron oxide core-shell nanoparticles (Fe@FexOy) are a versatile support for immobilizing catalytic metals. Fe@Fe xOy decorated with Pd (Fe@FexOy/Pd) exhibits high catalytic activity toward Suzuki-Miyaura cross-coupling reactions in aqueous solution at room temperature in air. The Royal Society of Chemistry.
- Zhou, Shuai,Johnson, Melanie,Veinot, Jonathan G. C.
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- C?H Arylation on Nickel Nanoparticles Monitored by In Situ Surface-Enhanced Raman Spectroscopy
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Bifunctional Au@Ni core–satellite nanostructures synthesized by a one-step assembly method were employed for in situ surface-enhanced Raman spectroscopic (SERS) monitoring of Ni-catalyzed C?C bond-forming reactions. Surprisingly, the reaction that was thought to be an Ullmann-type self-coupling reaction, was found to be a cross-coupling reaction proceeding by photoinduced aromatic C?H bond arylation. In situ SERS monitoring enabled the discovery, and a series of biphenyl compounds were synthesized photocatalytically, and at room temperature, using cheap Ni nanoparticle catalysts.
- Li, Yonglong,Hu, Yanfang,Shi, Faxing,Li, Haixia,Xie, Wei,Chen, Jun
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- PEPPSI-type complexes with small NHC ligands obtained according to the new method efficiently catalyzed Suzuki-Miyaura reaction
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A series of 13 new PEPPSI-type complexes with small NHC ligands and differently substituted imidazoles were prepared using as substrates [Pd(μ-X)X(bmim-y)]2 dimer or imidazole complexes PdCl2(imidazole)2. Improvement of th
- Sikorski,Zawartka,Trzeciak
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- Ferrocenyl monophosphine ligands: Synthesis and applications in the Suzuki-Miyaura coupling of aryl chlorides
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Ferrocenyl monophosphine ligands have been developed by a method based on palladium-catalyzed Suzuki-Miyaura coupling. The modular procedure creates a rapid synthesis of phosphines with diverse properties. The electron-rich phosphines have been successfully applied to the Suzuki-Miyaura coupling of activated and deactivated aryl chlorides, with low catalyst loading being feasible in the synthesis of tris-ortho-substituted biaryls.
- Baillie, Colin,Zhang, Lixin,Xiao, Jianliang
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- Nanocellulose Supported PdNPs as in situ Formed Nano Catalyst for the Suzuki Coupling Reaction in Aqueous Media: A Green Approach and Waste to Wealth
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An effective and highly sustainable method has been developed for the Suzuki coupling reaction of aryl halides and phenylboronic acid using in situ generated nacocellulose (NC) supported palladium nanoparticles (Pd@NC NPs) as heterogeneous catalysts in water. The formation of PdNPs was observed in the absence of additional reagents, during the course of the Suzuki reaction from NC and Pd(OAc)2. In situ formed Pd@NC NPs have been systematically characterized using TEM, EDX, XRD and FT-IR techniques. The in situ generated catalyst was separated and studied for its successful reusability up to 11 cycles. The application of aqueous media, use of in situ formed catalyst, mild reaction conditions, absence of volatile organic solvents, broad substrate scope, high product isolated yields are the significant developments of this protocol. The nanocellulose used for this protocol has been generated form the waste cotton cloth and hence it is an example for the waste to wealth and sustainable approach.
- Aabaka, Sreenath Reddy,Mao, Jincheng,Lavanya, Mallu,Venkateswarlu, Katta,Huang, Zhiyu,Mao, Jinhua,Yang, Xiaojiang,Lin, Chong
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- Suzuki-miyaura cross-coupling of 1,8-diaminonaphthalene (dan)-protected arylboronic acids
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We report a Suzuki-Miyaura cross-coupling reaction of 1,8-diaminonaphthalene (dan)-protected arylboronic acids in the presence of KOt-Bu, which does not require the removal of the dan moiety. Notably, the use of aryl-B(dan) in the Suzuki-Miyaura reaction provides a complementary solution to the protodeboronation problems. The base KOt-Bu plays a crucial role for the promotion of these cross-coupling reactions as it enables the formation of a borate salt. This reaction protocol was extended to the one-pot sequential Suzuki-Miyaura cross-coupling reaction of 4-[(pin)B]C6H4-B(dan), wherein the "less reactive" aryl-B(dan) moiety was cross-coupled preferentially.
- Mutoh, Yuichiro,Yamamoto, Kensuke,Saito, Shinichi
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- Preparation of monodentate phosphinite ligands: their applications in palladium catalyzed Suzuki reactions
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Two phosphinites 2,6-OMe, 4-Me, 1-OPR2C6H2 (5a: R=Ph; 5b: R=tBu) were prepared in good yields. Two methoxy groups are placed on the 2,6 positions of the phosphinites deliberately thereby to avoid a plausible orthometallation process while coordinating toward palladium metal. Further reaction of 5a with PdCl2 in the ratio of 2:1 and 1:1 gave 5a ligated palladium complexes {(5a)PdCl(μ-Cl)}2 7a and {(5a)2PdCl2} 8a, respectively. As revealed from their crystal structures, the former is a dimeric complex with anticipated molecular arrangement; nevertheless, the latter is a monomeric complex with unexpected, energetically unfavorable cis form. By contrast, only dimeric form was observed from the reaction of 5b with PdCl2. It is believed that the bulky substituents, tBu, on 5b prevent the formation of a monomeric complex in cis form. Fair to good efficiencies were observed for the Suzuki-Miyaura cross-coupling reactions employed in situ-prepared 5/Pd(OAc)2 as the catalytic precursor.
- Cheng, Yan-Huei,Weng, Chia-Ming,Hong, Fung-E.
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- Palladium nanoparticles decorated into a biguanidine modified-KIT-5 mesoporous structure: A recoverable nanocatalyst for ultrasound-assisted Suzuki-Miyaura cross-coupling
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In the current research work, a new KIT-5-biguanidine-Pd(0) catalyst was prepared and applied to ultrasound-assisted Suzuki-Miyaura cross-coupling reactions using ultrasound waves at ambient temperature. The ultrasound-assisted method is a green and efficient method for C-C coupling. Many parameters of the Suzuki coupling reaction were examined, such as the irradiation time, the types of organic and inorganic bases, the types of aprotic and protic solvents, and the dosage (mol%) of catalyst. Also, the results showed that the yields from the ultrasound-assisted coupling reactions were higher than from non-irradiated reactions. The prepared catalyst was characterized via HR-TEM, SEM-EDX-mapping, FT-IR, ICP-AAS, BET-BJH, and XRD studies. The stability and catalytic performance of the prepared catalyst were good, and it could be reused 6 times without catalytic activity loss for the Suzuki-Miyaura cross-coupling reaction.
- Veisi, Hojat,Mirzaei, Amin,Mohammadi, Pourya
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- Composition Control Synthesis and Catalytic Properties in the Suzuki Reaction of Bimetallic PdSn Nanoparticles
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We have successfully prepared 6.5 nm palladium tin (PdSn) alloy nanoparticles (NPs) with tunable compositions by high-temperature reduction of tin acetate and palladium bromide in the presence of oleylamine and trioctylphosphine. The catalytic activities of PdSn NPs with different compositions were evaluated through Suzuki reactions. The PdSn nanocatalysts show better catalytic activity on Suzuki reactions than an equal amount of pure Pd NPs, and their catalytic activities are highly composition dependent. Among these NPs, Pd63Sn37/C NPs exhibited the highest catalytic performance with higher reaction activity, lower Pd leaching properties, and higher stability even after eight recycle reactions.
- Li, Yong,Wang, Tian,Yang, Bo,Tian, Xi-Ke
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- A new air and moisture stable robust bio-polymer based palladium catalyst for highly efficient synthesis of biaryl compounds
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The designs of robust natural polymer based catalysts are important for catalytic systems in the view of industrial purposes and green chemistry. In this study, a new air and moisture stable robust starch-based Pd(II) catalyst was designed and characterized with different analytical techniques. Catalytic behavior of the prepared robust palladium(II) catalyst was investigated in the Suzuki coupling reactions of aryl iodides, aryl bromides and aryl chlorides with phenyl boronic acid under microwave irradiation using very short reaction time. Sustainability and reusability of the catalyst was also explored under benign conditions. As a result of the catalytic tests, the green catalyst gave excellent biphenyl yields, TONs and TOFs with very low catalyst loading. More importantly, the robust catalyst has showed that it can be reused several times without important loses from its activity in the coupling reactions. The study showed that the robust starch-based Pd(II) catalyst had more advantages than other catalysts reported in the literature due to its economic, sustainable, thermal durable, environmentally friendly and practice properties.
- Baran, Talat,Y?lmaz Baran, Nuray,Mente?, Ayfer
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- Fabrication and application of cellulose Schiff base supported Pd(II) catalyst for fast and simple synthesis of biaryls via Suzuki coupling reaction
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Bio-supported catalysts, due to their green nature, are promising materials for coupling reactions. In this paper, the design and application of a new green cellulose Schiff base supported Pd(II) catalyst (CL-Sc-Pd) for the synthesis of different biaryls under microwave irradiation without the use of any organic solvent is reported. Firstly, a silane-modified cellulose Schiff base (CL-Sc) was synthesized as a support material, and then its heterogonous Pd(II) catalyst was easily prepared in water for the Suzuki coupling reaction. The synthesized materials were then characterized with various analytical tools. Finally, the catalytic performance of the green catalyst was investigated towards various C[sbnd]C reactions using a green, simple and fast microwave technique. The catalyst indicated excellent selectivity and activity in a very short time (6?min) under a solvent-free media. In addition, outstanding TON (19,800) and TOF (198,000) values were obtained with the green Pd(II) catalyst. The longevity of the green Pd(II) catalyst was studied and it was found to be reusable for at least eight runs. CL-Sc-Pd catalyst showed perfect catalytic efficiency for the Suzuki C[sbnd]C reaction when it was compared to commercial palladium catalysts.
- Y?lmaz Baran, Nuray,Baran, Talat,Mente?, Ayfer
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- Room-temperature nickel-catalysed Suzuki-Miyaura reactions of aryl sulfonates/halides with arylboronic acids
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Room-temperature Suzuki-Miyaura aryl-aryl cross-coupling reactions have been achieved in high yields by using an easily accessible, air-stable Ni II-(σ-aryl) complex as precatalyst without either the pretreatment of organometallic reagents or the presence of external reductants. The NiII complex, in conjunction with monophosphane ligands such as PCy3·HBF4 or PPh3, allowed the efficient cross-coupling of aryl sulfonates (OTs, OMs) and/or halides (Cl, Br, I) with arylboronic acids at room temperature in toluene/water in the presence of K 2CO3 as base. Room-temperature Suzuki-Miyaura reactions of aryl sulfonates (OTs, OMs) and/or halides (Cl, Br, I) with arylboronic acids have been achieved by using aneasily accessible, air-stable Ni II-(σ-aryl) complex as precatalyst without the pretreatment of organometallic reagents or the presence of external reductants. Copyright
- Fan, Xin-Heng,Yang, Lian-Ming
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- Highly efficient, quick and green synthesis of biarlys with chitosan supported catalyst using microwave irradiation in the absence of solvent
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The aim of this study was to develop a quick reaction that had high activity with a small amount of catalyst, which could be an eco-friendly alternative technique for the synthesis of biarlys in Suzuki coupling reactions. First, a novel chitosan Schiff base supported Pd(II) catalyst was synthesized, and its structure was illuminated with FTIR, 1H NMR, 13C NMR, TG/DTG, SEM/EDAX, XRD, ICP-OES, UV-vis, magnetic moment, and molar conductivity techniques. Subsequently, the catalytic activity of the catalyst was tested in Suzuki C-C reactions under microwave irradiation using a solvent-free reaction condition. The catalytic tests showed an excellent activity with a small load of the catalyst (0.02 mol%) in 4 min. The catalyst showed seven runs without loss of activity, and high values of turnover numbers (TON) and turnover frequency (TOF) were obtained. The novel biopolymer supported Pd(II) catalyst provided much faster reaction times, higher yields, and reusability under microwave heating compared to classic heating methods.
- Baran, Talat,A?iks?z, Eda,Mente?, Ayfer
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- Efficient Suzuki-Miyaura coupling reaction in water: Stabilized Pd o-Montmorillonite clay composites catalyzed reaction
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The Pdo-nanoparticles, generated into the nanopores of modified Montmorillonite clay, were evaluated for catalytic performance for the Suzuki-Miyaura cross coupling reactions. The modification of Montmorillonite clay was carried out by activating with H2SO4 under controlled conditions for generating nanopores on the surface for serving as a 'Host' for the Pdo-nanoparticles which were prepared in situ by loading of K2PdCl4 through incipient wetness impregnation technique followed by reduction with hydrazine hydrate. The Powder-XRD, SEM-EDX, TEM, N2 adsorption, XPS, etc. analyses were carried out to characterize the stabilized nanoparticles as well as the support. The TEM study reveals that the evenly distributed Pdo-nanoparticles are below 10 nm size and exhibit face centred cubic (fcc) lattice geometry. The supported Pdo-nanoparticles exhibit efficient heterogeneous catalytic performance for the Suzuki-Miyaura coupling reactions between different organoboronic acids and aryl halides for preparing the cross-coupling products in 94% isolated yield (maximum) and 100% selectivity in water under ligand free conditions. The nanocatalysts could be recycled at least three consecutive runs with a little loss of their catalytic activities.
- Borah, Bibek Jyoti,Borah, Subrat Jyoti,Saikia, Kokil,Dutta, Dipak Kumar
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- Superparamagnetic nanoparticle-supported catalysis of Suzuki cross-coupling reactions
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(Figure Presented) Emulsion polymerization was examined as a novel route for the synthesis of core/shell superparamagnetic nanoparticles consisting of a highly crystalline γ-Fe2O3 core and a very thin polymeric shell wall. These nanoparticles were used as soluble supports for immobilizing Pd catalysts to promote Suzuki cross-coupling reactions. Recovery of catalysts was facilely achieved by applying a permanent magnet externally. Isolated catalysts were reused for new rounds of reactions without significant loss of their catalytic activity.
- Stevens, Philip D.,Fan, Jinda,Gardimalla, Hari M. R.,Yen, Max,Gao, Yong
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- A solid supported palladium(0) nano/microparticle catalyzed ultrasound induced continuous flow technique for large scale Suzuki reactions
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An ultrasound-induced continuous flow technique was developed for the solid supported palladium(0) nano/microparticle (SS-Pd) catalyzed Suzuki cross coupling reaction of haloarenes (chloro, bromo and iodo) with phenyl boronic acid on a gram scale. An externally conjugated reservoir was fitted for easy operation of the reaction in water under mild basic conditions. The SS-Pd catalyst was found to be very stable in aqueous media, easily separable and recyclable up to five runs without significant loss of activity. Furthermore, the scaling of the well known Suzuki reaction up to 5 g scale under mild ultrasonic irradiation can be of industrial interest in the future.
- Shil, Arun K.,Guha, Nitul Ranjan,Sharma, Dharminder,Das, Pralay
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- Exceptionally high turnover frequencies recorded for a new chitosan-based palladium(II) catalyst
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To be industrially feasible, and applicable in synthesis of fine chemicals, a catalyst has to possess high turnover number (TON) and turnover frequency (TOF). In this study, a new cross-linked chitosan derivative was synthesized by using 2,2′-pyridil as a cross-linking agent. 2,2′-Pyridil cross-linked chitosan was used to as a support material for palladium catalyst. Chitosan-pyridil-based Pd(II) catalyst was tested in the microwave-assisted synthesis of biaryls via Suzuki coupling reactions. The catalyst yielded remarkable TONs of up to 20,000 and TOFs of up to 240,964 by using very low catalyst loading (5 × 10-3% mol) in a short reaction time (5 min). The catalyst also showed a better recyclability.
- Baran, Talat,Sargin, Idris,Mente?, Ayfer,Kaya, Murat
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- Synthesis of a carbene transfer organometallic polymer and application to forming a recyclable heterogeneous catalyst for the Suzuki reactions of aryl chlorides
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An efficient and versatile synthetic approach to NHC-based organometallic polymers has been developed by a simple three-step synthesis. A novel brush polymer having imidazolium salt side chains (P2) was firstly synthesized through postpolymerization modification of P1, which permits access to Ag(i)-NHC-based side chain polymer (P3) at room temperature in high yield. P3 was applied as a carbene transfer agent to form a Pd-NHC-containing polymer (P4) by the transmetallation reaction of Ag(i)-NHCs in the side chains. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis indicated that 77% of Ag(i)-NHCs in the side chains of P3 were transmetallated. The resulting Pd-NHC-containing polymer (P4) showed high catalytic activity and reusability in the Suzuki reactions of aryl chlorides and aryl boronic acids. This novel Pd-NHC-containing polymeric catalyst was used five times and still remained active giving the desired biaryl products in 70% yield in the fifth run of the cross-coupling reaction of deactivated 4-chloroanisole with phenylboronic acid. The Royal Society of Chemistry 2009.
- Zeng, Xiaoming,Zhang, Tongxin,Qin, Yuancheng,Wei, Zhijun,Luo, Meiming
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- Eco-friendly functionalization of natural halloysite clay nanotube with ionic liquids by microwave irradiation for Suzuki coupling reaction
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Microwave assisted halloysite (HNT) external surface functionalization with ionic liquids is described. HNTs modification was achieved in two steps: a) grafting of 3-mercaptopropyl trimethoxysilane on the external surface of HNT by a microwave irradiation; b) anchorage of vinylimidazolium ionic liquids by a thiol-ene reaction. MW irradiation allowed us to obtain high loading onto the HNT surface compared to those obtained through conventional synthesis. Fourier transform infrared spectroscopy and thermogravimetric analysis confirmed that the grafting has occurred only on the external surface of HNT. Turbidimetric and dynamic light scattering analyses showed that the introduction of ionic liquid on the HNT surface involves the formation of aggregates. One of these materials has been used as support for Palladium particles and tested, as catalyst, in the Suzuki reaction between phenylboronic acid and some aryl halide to give the corresponding biaryl in high yield. A catalytic efficiency higher than conventionally used support was achieved.
- Massaro, Marina,Riela, Serena,Cavallaro, Giuseppe,Gruttadauria, Michelangelo,Milioto, Stefana,Noto, Renato,Lazzara, Giuseppe
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- Pd nanoparticles stabilized on the Schiff base-modified boehmite: Catalytic role in Suzuki coupling reaction and reduction of nitroarenes
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Palladium nanoparticles (Pd NPs) were decorated on Schiff base-modified boehmite (Sch-boehmite) particles via a simple method without deploying any additional reducing agents and their structure was confirmed by different characterization methods. The ensuing Pd NPs?Sch-boehmite was evaluated as a retrievable catalyst for multiple cycles in Suzuki cross-coupling reactions with extensive substrate tolerance to produce biaryls in high yields within 6 min, and the reduction of 2-nitroaniline (2-NA) and 4-nitrophenol (4-NP) at room temperature in 3–4 min, respectively. Moreover, Pd NPs?Sch-boehmite catalyst could be conveniently recovered and reused multiple times.
- Baran, Nuray Y?lmaz,Baran, Talat,Nasrollahzadeh, Mahmoud,Varma, Rajender S.
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- Palladium nanoparticles decorated on a novel polyazomethine as a highly productive and recyclable catalyst for Suzuki coupling reactions and 4-nitrophenol reduction
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This report displays the procedure in preparation of fast, highly productive, reusable, and easily retrievable Pd nanoparticles (NPs) as a heterogeneous catalyst (Pd NPs?P(3-MPAP)) immobilized on a novel polyazomethine with phenol group, Poly(3-methyl-4-((pyridin-2-ylmethylene)amino)phenol) (P(3-MPAP)), and the investigation of its catalytic efficiency in fabrication of several biaryl compounds by Suzuki coupling reactions and reduction of 4-nitrophenol to 4-aminophenol. The structures of the synthesized monomer, polymer support material and nanocatalyst were identified by UV–Vis, FT-IR, 1H NMR, TGA, XRD, SEM and EDS methods. The catalytic activity of Pd NPs?P(3-MPAP) catalyst in the synthesis of various biaryls by Suzuki coupling reactions was explored using microwave irradiation, which is rapid, easy, solventless and environmentally friendly method. The nanocatalyst presented outstanding advantageous methodology containing easy work-up with high reaction yield (99%) at very short reaction time (5 min) in solventless media using very low catalyst loading (0.007 mol%) in the synthesis of biaryls. Additionally, the harmful 4-nitrophenol was completely reduced to industrially useful 4-aminophenol in the presence of Pd NPs?P(3-MPAP) with low catalyst amount (1 mg), at very short reaction time (60s) without any toxic solvent (in water) at room temperature. Additionally, reproducibility test results for both catalytic reactions show that the highly productive nanocatalyst was easily retrievable and reusable for six and five sequential cycles, respectively, for Suzuki coupling reactions and reduction of 4-NP without any notable loss in its catalytic activity.
- Y?lmaz Baran
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- Ultrasound-accelerated synthesis of biphenyl compounds using novel Pd(0) nanoparticles immobilized on bio-composite
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This study describes (i) an eco-friendly approach for design of Pd(0) nanoparticles on a natural composite, which is composed of carboxymethyl cellulose/agar polysaccharides (CMC/AG), without using any toxic reducing agents and (ii) development of ultrasound assisted simple protocol for synthesis of biphenyl compounds. Chemical characterization studies of Pd(0) nanoparticles (Pd NPs@CMC/AG) revealed that size of the particles were in the range of 37–55 nm. Catalytic performance of Pd NPs@CMC/AG was evaluated in synthesis of various biphenyl compounds by using the ultrasound-assisted method that was developed in this study. Pd NPs@CMC/AG exhibited excellent catalytic performance by producing high reaction yields. In addition, Pd NPs@CMC/AG was successfully used up to six reaction cycles without losing its catalytic activity, indicating high reproducibility of Pd NPs@CMC/AG. Additionally, compared to conventional the methods, new ultrasound-assisted synthesis technique that was followed in this study exhibited some advantages such as shorter reaction time, greener reaction conditions, higher yields and easier work-up.
- Baran, Talat
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- Microwave assisted synthesis of biarlys by C-C coupling reactions with a new chitosan supported Pd(II) catalyst
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In this study a new type chitosan-based support has been produced for Pd(II) catalyst and its catalytic performance in Suzuki C-C reactions has been studied under microwave irradiation without using any solvent. The chemical identification of the catalyst was performed using TG/DTG, FTIR, UV-Vis ICP-OES, SEM/EDAX, 13C NMR, molar conductivity, XRD and magnetic moment techniques. The performance of this new Pd(II) catalyst was studied in Suzuki C-C reactions. The Pd(II) catalyst exhibited a good catalytic performance in very short time (4 min) by giving high TONs and TOFs with low amount of the catalyst (0.015 mol%). The catalyst also had reusability and did not lose its activity until six runs.
- Baran, Talat,Mente?, Ayfer
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- Facile synthesis of NC(sp3)O pincer palladium complexes and their use as efficient catalysts for Suzuki-Miyaura reaction of aryl bromides in aqueous medium
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Two NC(sp3)O pincer palladium(II) complexes 3a-3b were readily prepared in high yields in only two steps. Of the first step, catalytic hydrophosphination of 2-alkenoylpyridines and subsequent in situ phosphine oxidation produced the NC(sp3)O pincer preligands 2a-2b. The second step is palladation of the preligands 2a-2b where PdCl2 was used as the Pd source to afford the desired Pd pincers 3a-3b via C(sp3)-H bond activation. Single crystal X-ray diffraction analysis of complex 3a unambiguously confirmed the NCO tridentate coordination mode of the complexes. The two complexes 3a-3b were applied to catalyze the Suzuki-Miyaura reaction. Complex 3b was found to be more efficient and exhibited very high activity in the Suzuki reaction of structurally diverse aryl bromides with arylboronic acids in aqueous ethanol under air. At a reaction temperature of 70 °C, a TON of up to 1.9 × 105 and a TOF of up to 9800 h?1 were achieved. At lower temperatures 3b was still very active, giving a TON of up to 9.5 × 103 and a TOF of up to 3900 h?1 at room temperature.
- Gong, Jun-Fang,Li, Nan,Pan, Ya-Ping,Song, Mao-Ping,Yang, Jing-Jing,Zhu, Zhi-Wu
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- Green heterogeneous Pd(II) catalyst produced from chitosan-cellulose micro beads for green synthesis of biaryls
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In green catalyst systems, both the catalyst and the technique should be environmentally safe. In this study we designed a green palladium(II) catalyst for microwave-assisted Suzuki [Formula presented] coupling reactions. The catalyst support was produced from biopolymers; chitosan and cellulose. The catalytic activity of the catalyst was tested on 16 substrates in solvent-free media and compared with those of commercial palladium salts. Reusability tests were done. The catalyst was also used in conventional reflux-heating system to demonstrate the efficiency of microwave heating method. We recorded high activity, selectivity and excellent TONs (6600) and TOFs (82500) just using a small catalyst loading (1.5?×?10?3?mol%) in short reaction time (5?min). The catalyst exhibited a long lifetime (9 runs). The findings indicated that both green chitosan/cellulose-Pd(II) catalyst and the microwave heating are suitable for synthesis of biaryl compounds by using Suzuki [Formula presented] coupling reactions.
- Baran, Talat,Sargin, Idris,Kaya, Murat,Mente?, Ayfer
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- Palladium nanoparticles stabilized by phosphine ligand for aqueous phase room temperature suzuki-Miyaura coupling
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Water soluble phosphine ligand triphenylphosphine-3,3′,3″-trisulfonic acid trisodium salt (TPPTS) was used as the stabilizer as well as the activator to the palladium nanoparticles, which showed a high catalytic performance for aqueous phase Suzuki-Miyaura coupling reaction at room temperature.
- Ge, Jiyuan,Jiang, Jian,Yuan, Chenhuan,Zhang, Chaozhi,Liu, Minghua
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- Synthesis and investigation of 1,6-bis-di-tert-butylphosphinohexane and its application in Suzuki-Miyaura coupling
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Palladium catalysts have excellent compounds used in generating difficult carbon-carbon bonds. The development of these palladium catalysts has been the attention of much research. The use of alkyl-phosphines has led to many very active, bulky ligands for
- Mitchell, John M.,Brown, William S.
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- Highly active, air-stable palladium catalysts for the C-C and C-S bond-forming reactions of vinyl and aryl chlorides: Use of commercially available [(t-Bu)2P(OH)]2PdCl2, [(t-Bu)2P(OH)PdCl2]2, and [[(t-Bu)2PO···H·· ·OP(t-B0. u)2]PdCl]2 as catalysts
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Air-stable palladium complexes [(t-Bu)2P(OH)]2PdCl2, [(t-Bu)2P(OH)PdCl2]2, and [[(t-Bu)2PO···H··· OP(t-Bu)2]PdCl]2 serve as efficient catalysts for a variety of cross-coupling reactions of vinyl and aryl chlorides with arylboronic acids, arylzinc reagents, and thiols to yield the corresponding styrene derivatives, biaryls, and thioethers. 31P NMR and mechanistic studies argue that the phosphinous acid ligands in the complexes can be deprotonated in the presence of a base to yield an electron-rich anionic species, which is likely a catalyst intermediate, and dimeric [[(t-Bu)2PO···H·· ·OP(t-Bu)2]PdCl]2 was isolated and cystallographically characterized. These anionic complexes are anticipated not only to accelerate the rate-determining oxidative addition of aryl chlorides but also to stabilize the palladium complexes in the catalytic cycle.
- Li, George Y.
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- Carboxymethyl chitosan Schiff base supported heterogeneous palladium(II) catalysts for Suzuki cross-coupling reaction
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In this study, two new O-carboxymethyl chitosan Schiff bases supported Pd(II) catalyst were synthesized (OCMCS-3aPd and OCMCS-4aPd). The catalysts were characterized with FTIR, TG/DTG, SEM/EDAX, XRD, ICP-OES, UV-vis, magnetic moment and molar conductivity. The catalytic activities of these catalysts were tested in the synthesis of biaryl compounds by Suzuki cross-coupling reactions. Characterizations of the biaryls were performed with GC-MS and 1H NMR. In synthesis of the biaryl compounds in the presence of the Pd(II) catalyst, high selectivity was observed; no homo-coupling byproducts were detected in the spectra. A reusability test demonstrated that the catalysts were highly efficient even after ten run. The mercury poisoning and leaching tests indicated that the catalysts have heterogeneous nature.
- Baran, Talat,A?iks?z, Eda,Mente?, Ayfer
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- Cobalt-Catalyzed Cross-Coupling Reactions of Aryl Triflates and Lithium Arylborates
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A catalyst system comprising CoCl2/IAd·HBF4 enables the Suzuki-Miyaura cross-coupling reaction of a broad range of aryl triflates and arylboronic esters that are activated by n-butyllithium.
- Duong, Hung A.,Yeow, Zong-Han,Tiong, Yong-Lun,Mohamad Kamal, Nur Haidah Binte,Wu, Wenqin
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- Suzuki reactions of aryl bromides catalyzed by amidoxime fibers-palladiumII complex
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Amidoxime fibers-palladiumII complexes [PdII-AOFs] were synthesized by combining PdCl2 with amidoxime fibers. Pd II-AOFs are novel phosphine-free recyclable heterogeneous catalysts for Suzuki coupling reaction of aryl bromides with phenylboronic acid to provide the corresponding products in high yields. The heterogeneous catalyst can be readily recovered by simple filtration and reused several times without significant loss in its activity.
- Wu, Zhi-Chuan,Huang, Ya,Lu, Ye-Neng,Tao, Ting-Xian,Zhang, Ze
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- Palladium supported on cross-linked imidazolium network on silica as highly sustainable catalysts for the Suzuki reaction under flow conditions
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Highly cross-linked imidazolium-based materials, obtained by radical oligomerization of bis-vinylimidazolium salts in the presence of 3-mercaptopropyl-modified silica gel, were used as supports for palladium catalysts. Thanks to the high imidazolium loading these materials were able to support a high amount of the metal (10 wt%). Such materials were characterized by several techniques (13C magic angle spinning nuclear magnetic resonance, the Brunauer-Emmett-Teller technique, X-ray photoelectron spectroscopy, and transmission electron microscopy). The palladium catalysts displayed good activity allowing the synthesis of several biphenyl compounds in high yields working with only 0.1 mol% of palladium loading at 50°C in ethanol/water under batch condition. Moreover, a flow apparatus, to optimize the efficiency of the isolation of the pure products and minimize waste (E-factor), was investigated. For the first time the palladium catalyst and base (K 2CO3) were placed in two separate columns allowing an easy recovery of the products with very low E-factor values (4). Waste production was reduced by over 99% compared to classic batch conditions. Because of the high Pd loading only 42 mg of catalysts were employed in the Suzuki reaction between 160 mmol of 4-bromotoluene and 180 mmol of phenylboronic acid. No loss in activity was observed. Copyright
- Pavia, Cinzia,Ballerini, Eleonora,Bivona, Lucia Anna,Giacalone, Francesco,Aprile, Carmela,Vaccaro, Luigi,Gruttadauria, Michelangelo
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- Highly efficient Suzuki cross-coupling reaction of biomaterial supported catalyst derived from glyoxal and chitosan
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In this study a new chitosan based water soluble Schiff base was produced through carboxymethylation of chitosan and its Pd(II) complex were synthesized and characterized by FTIR, 1H NMR, 13C CP-MAS NMR, TG/DTG, SEM/EDAX, XRD, ICP-OE
- Baran, Talat,Mente?, Ayfer
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- Highly efficient suzuki coupling of aryl chlorides in a continuous flow capillary microreactor
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The Suzuki reactions of aryl chlorides containing both electron-donating and electron-withdrawing groups with aryl boronic acid, catalyzed by a simple non-phosphine ligand catalyst system, Pd(OAc)2/DABCO, were performed in a continuous capillary microreactor at 50C. In the microreactor, the coupling product was obtained mostly in near quantitative yield within a four hour residence time. In contrast, the conversions were only 12-69% in batch reactions.
- Jin, Jie,Cai, Min-Min,Li, Jian-Xin
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- A simple, efficient and green approach for the synthesis of palladium nanoparticles using Oxytocin: Application for ligand free Suzuki reaction and total synthesis of aspongpyrazine A
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A novel, green, eco-friendly and cost-effective biological route for the synthesis of palladium nanoparticles (PdNPs) from commercially available palladium chloride and easily isolable hormone Oxytocin as reducing agent is reported here. Characterization of PdNPs were done using various techniques, UV–visible spectroscopy, XRD, TEM and EDAX, characterization data confirmed the formation of Pd0 from Pd2+. The size of synthesized PdNPs were 15–20 nm. The scope of Pd nanoparticles was studied for the C–C bond formation Suzuki reaction. The catalytic activity of PdNPs was excellent in short reaction time and reaction works in green solvent water as well as catalyst can be recycled. Simple and efficient approach for total synthesis of aspongpyrazine A of the recently isolated natural substance is described.
- Bendre, Ameya D.,Kodam, Kisan M.,Patil, Viraj P.,Terdale, Santosh S.,Waghmode, Suresh B.
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- Highly effective and recoverable Pd(II) catalyst immobilized on thermally stable Schiff base polymer containing phenol group: Production, characterization and application in Suzuki coupling reactions
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In this study, a novel highly efficient, recoverable, sustainable, and thermally stable Schiff base polymer-Pd(II) catalyst was designed for Suzuki coupling reactions in synthesis of biaryl compounds for the first time. Firstly, a novel Schiff base polymer containing phenol, Poly(4-((pyridine-2ylimino)methyl)benzene-1,3-diol) (P (4-PMB)), which was used as a support material in catalyst design, was synthesized in aqueous alkaline medium via oxidative polycondensation of 4-((pyridine-2-ylimino)methyl)benzene-1,3-diol (4-PMB) with NaOCl oxidant. The effects of oxidant concentration, polymerization temperature, and time on yield and molecular weight of the polymer were investigated. The structures of the synthesized compounds were illuminated by UV–Vis, FTIR, 1HNMR, XRD, TG/DTG, and SEM/EDAX methods. Then, Pd(II) complex of P (4-PMB) was produced, and its catalytic performance was tested in the synthesis of various biaryl compounds by Suzuki reactions using microwave irradiation technique which is a highly effective, fast, solvent-free and green method. The designed Pd(II) catalyst exhibited superior catalytic effect against syntheses of various biaryl compounds with high conversion yields (99%) and very low catalyst loading (0.01 mol%) for 5 min. Recyclability and reproducibility tests showed that the catalyst could be reused for seven successive runs without any great loss of its catalytic performance (84%).
- Y?lmaz Baran, Nuray,Baran, Talat,Mente?, Ayfer,Karak??la, Meral,Sa?ak, Mehmet
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- Suzuki cross-coupling in aqueous media
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We report a simple and efficient procedure for the ligand-free as well as ligand-assisted Suzuki reaction in both pure water and aqueous media. The cross-coupling reactions proceed successfully using phenylboronic acid or potassium phenyltrifluoroborate as a nucleophilic coupling partner. The method can be effectively applied to both activated and deactivated aryl halides yielding quantitative conversions. The catalytic activity of couplings performed in pure water increases when utilizing supramolecular additives, but decreases under standard phase-transfer conditions. Finally, the palladium loading is reducible from 3.0 mol% to 0.4 mol% without any loss of conversion.
- Hoffmann, Ina,Blumenr?der, Bettina,Onodi Neé Thumann, Silvia,Dommer, Sabine,Schatz, Jürgen
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- Construction of new biopolymer (chitosan)-based pincer-type Pd(II) complex and its catalytic application in Suzuki cross coupling reactions
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In this paper we described the fabrication, characterization and application of a new biopolymer (chitosan)-based pincer-type Pd(II) catalyst in Suzuki cross coupling reactions using a non-toxic, cheap, eco-friendly and practical method. The catalytic activity tests showed remarkable product yields as well as TON (19800) and TOF (330000) values with a small catalyst loading. In addition, the catalyst indicated good recyclability in the Suzuki C-C reaction. This biopolymer supported catalyst can be used with various catalyst systems due to its unique properties, such as being inert, green in nature, low cost and chemically durable.
- Baran, Talat,Mente?, Ayfer
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- Functionalized chitosan as a novel support for stabilizing palladium in Suzuki reactions
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Chitosan is a versatile polysaccharide in different domains due to facile modification and good biodegradability. In this paper, taking advantage of such functional properties, we have developed a stabilizer agent [OCMCS-SB] produced from chitosan, and palladium was successfully immobilized on this designed stabilizer [OCMCS-SB-Pd(II)]. The obtained complex was illuminated by 13C CP-MAS NMR, FT-IR, TGA, XRD, XPS, SEM, TEM and ICP-OES analyses. Due to the interactions of primary hydroxyl groups on chitosan, Schiff base and carboxy groups, the Pd complex showed excellent reactivity (up to 99 %) and stability towards Suzuki reactions in eco-friendly medium. Subsequently, the reusability experiments for OCMCS-SB-Pd(II) formed from chitosan were examined in five consecutive cycles, which showed no appreciable decrease in activity. Furthermore, a reasonably trifunctional complex structure was proposed. The present bio-based system offers a promising approach in utilizing such biopolymers in organic transformations.
- Dong, Yahao,Bi, Jiajun,Ming, Shujun,Zhang, Shoute,Zhu, Dajian,Meng, Di,Li, Tao
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- A new chitosan Schiff base supported Pd(II) complex for microwave-assisted synthesis of biaryls compounds
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In this study, a new heterogeneous palladium (II) catalyst that contains O-carboxymethyl chitosan Schiff base has been designed for Suzuki coupling reactions. The chemical structures of the synthesized catalyst were characterized with the FTIR, TG/DTG, ICP-OES, SEM/EDAX, 1H NMR, 13C NMR, GC/MS, XRD, and magnetic moment techniques. The reusability and catalytic behavior of heterogeneous catalyst was tested towards Suzuki reactions. As a result of the tests, excellent selectivity was obtained, and by-products of homo coupling were not seen in the spectra. The biaryls products were identified on a GC/MS. In addition, it was determined in the reusability tests that the catalysts could be used several times (seven runs). More importantly, with very low catalyst loading (6?×?10?3?mol %) in very short reaction time (5?min), chitosan Schiff base supported Pd(II) complex gave high TON and TOF values. These findings showed that Schiff base supported Pd(II) catalyst is suitable for Suzuki cross coupling reactions.
- Baran, Talat
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- In situ generation of palladium nanoparticles: A simple and highly active protocol for oxygen-promoted ligand-free suzuki coupling reaction of aryl chlorides
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An oxygen-promoted ligand-free Suzuki coupling reaction catalyzed by in situ generated palladium nanoparticles in PEG-400 under aerobic conditions has been demonstrated. The reaction was highly efficient for coupling aryl chlorides with phenylboronic acid in short times under mild conditions.
- Han, Wei,Liu, Chun,Jin, Zi-Lin
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- S‐Benzylisothiourea Complex of Palladium Supported on Modified Mesoporous Magnetic Nanoparticles (Pd-SBTU@Fe3O4@SBA-3) as Sustainable Environmental Catalyst for Suzuki and Stille Reactions
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Abstract: A new and efficient magnetic mesoporous material has been designed and prepared via immobilization of S‐benzylisothiourea complex of palladium on SBA-3 mesoporous silica magnetite nanoparticles. This novel, architecturally interesting magnetic nanocomposite was fully characterized using different analytical techniques such as FT-IR, BET, FE-SEM, ICP-OES and TGA. Catalytic activity of this material was successfully explored in carbon–carbon cross-coupling reactions (Suzuki and Stille reactions). The stability of the catalytic activity was examined using reusability test through four consecutive batch runs. Green conditions of the reactions, easy separation, short reaction times, reusability of the catalyst, and excellent yields of products make the present protocol practical and sustainable among the similar reported cross-coupling reactions. Graphical Abstract: [Figure not available: see fulltext.].
- Ghorbani-Choghamarani, Arash,Heidarnezhad, Zahra,Taherinia, Zahra
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- Nickel-Catalyzed Direct Cross-Coupling of Aryl Sulfonium Salt with Aryl Bromide
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The direct cross-couplings of aryl sulfonium salts with aryl halides could be achieved by using nickel as a reaction catalyst. The reactions proceeded efficiently via C-S bond activation in the presence of magnesium turnings and lithium chloride in THF at ambient temperature to afford the corresponding biaryls in moderate to good yields, potentially serving as an attractive alternative to conventional cross-coupling reactions employing preprepared organometallic reagents.
- Ma, Na-Na,Ren, Jing-Ao,Liu, Xiang,Chu, Xue-Qiang,Rao, Weidong,Shen, Zhi-Liang
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p. 1953 - 1957
(2022/03/27)
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- Highly selective Suzuki reaction catalysed by a molecular Pd-P-MOF catalyst under mild conditions: Role of ligands and palladium speciation
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Cross-coupling reactions are a fundamental tool in the large scale synthesis of pharma-, agro-and fine chemicals. Homogeneous palladium complexes remain the state-of-the-art catalysts even though the use of heterogeneous palladium catalysts may have advantages such as catalyst recyclability, precious metal recovery and the possibility of being used in continuous flow operation. However, this is predicated on achieving acceptable process stability and selectivity levels without side reactions, such as e.g. hydrodehalogenation of aryl halides. We report a molecularly-defined heterogeneous palladium catalyst based on a phosphine-metal-organic framework (P-MOF) ligand system. This catalyst performed Suzuki reactions in exceptionally mild conditions while displaying a unique selectivity, higher than that achieved using Pd(PPh3)4, a standard homogeneous catalyst. The new palladium P-MOF catalyst was active for a wide range of substrates. Determination of the palladium speciation showed that molecularly-defined palladium-phosphine sites catalyse the Suzuki cross-coupling with very high selectivity, and that, when formed, palladium nanoparticles promote hydrodehalogenation. The fraction of molecularly defined palladium is maximized by having excess of phosphine ligand in the system. This journal is
- Bachmann, Stephan,Cartagenova, Daniele,Newton, Mark A.,Püntener, Kurt,Peixoto Esteves, Fabio A.,Ranocchiari, Marco,Rohrbach, Thomas,Scalone, Michelangelo,Van Bokhoven, Jeroen A.,Zimmermann, Patrik P.
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p. 954 - 961
(2022/02/17)
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- Palladium Nanoparticles Supported on Cellulosic Paper as Multifunctional Catalyst for Coupling and Hydrogenation Reactions
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Hallmark of a successful catalyst is its high efficiency, economic aspects, operational simplicity, extensive reusability, higher environment friendliness, and potential use in multiple industrial applications. Herein, a facile protocol involving a cataly
- Kalanthoden, Abdul Nasar,Zahir, Md. Hasan,Aziz, Md. Abdul,Al-Najar, Basmah,Rani, S. Kutti,Shaikh, M. Nasiruzzaman
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- Synthesis and Evaluation of Novel Planar-Chiral Monophosphine Ligands Bearing Ferrocene-Triazole Backbones
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We prepared novel planar chiral monophosphine ligands bearing ferrocene-triazole backbones. These ligands were produced in a series of steps that included triazole synthesis by diastereoselective azidation and Huisgen cycloaddition of (S)-Ugi's amine, followed by methylation and phosphine introduction. This method was applicable to the preparation of various analogues due to the wide substrate scope of the Huisgen cycloaddition reaction. These ligands showed good catalytic activity in Suzuki–Miyaura coupling reactions, especially those involving bulky substrates. Furthermore, the optically active versions of these ligands were used in the asymmetric Suzuki–Miyaura coupling reaction to produce the axial chiral binaphthyl compound with moderate enantioselectivity. The ligand developed in this study is the first triazole-type biaryl- monophosphine ligand that can be used in asymmetric reactions, and it is expected to be a new tool for the accessing chiral compounds.
- Sakai, Suguru,Kanemoto, Kazuya,Fukuzawa, Shin-ichi
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- A Pd(II) Magnetically Retrievable Catalyst for Hiyama Reaction: Functionalization of Magnetic Mesoporous Silica via Click Reaction
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Abstract: A nitrogen ligand, i.e. 1,3-di-(o-aminophenoxy)-2-propyl propargyl ether (DPPE), has been synthesized and characterized. Magnetic mesoporous silica composite (MNP@SiO2-SBA) was obtained via embedding magnetite nano-particles (MNPs) between SBA-15 channels. DPPE palladium dichloride (MNP@SiO2-SBA-DPPE-Pd(II)) was then prepared via click chemistry and fully characterized. The Hiyama reaction conditions including solvent, amount of catalyst, base and temperature were optimized for the prepared catalyst. The activity and recyclability of supported magnetic Pd(II) catalyst were evaluated under the optimal reaction conditions. The catalyst was easily separated magnetically, reused in five runs sequentially, and no significant loss of activity was observed. Graphical Abstract: [Figure not available: see fulltext.]
- Esquivel, Dolores,Mansoori, Yagoub,Mousavi, Samira,Navarro, Ma Angeles,Nuri, Ayat
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- Palladium Immobilized on a Polyimide Covalent Organic Framework: An Efficient and Recyclable Heterogeneous Catalyst for the Suzuki–Miyaura Coupling Reaction and Nitroarene Reduction in Water
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An efficient and recyclable Pd nano-catalyst was developed via immobilization of Pd nanoparticles on polyimide linked covalent organic frameworks (PCOFs) that was facilely prepared through condensation of melamine and 3,3′,4,4′-biphenyltetracarboxylic dianhydride. The Pd nanoparticles (Pd NPs) catalyst was thoroughly characterized by FT-IR, XRD, SEM, TEM. Furthermore, the catalytic activity of Pd NPs catalyst was evaluated by Suzuki–Miyaura coupling reaction and nitroarene reduction in water, respectively. The excellent yields of corresponding products revealing revealed that the Pd NPs catalyst could be applied as an efficient and reusable heterogeneous catalyst for above two reactions. Graphical Abstract: [Figure not available: see fulltext.]
- Dong, Zhenhua,Pan, Hongguo,Gao, Pengwei,Xiao, Yongmei,Fan, Lulu,Chen, Jing,Wang, Wentao
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p. 299 - 306
(2021/05/10)
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- Preparation of Ni-microsphere and Cu-MOF using aspartic acid as coordinating ligand and study of their catalytic properties in Stille and sulfoxidation reactions
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In this study, the thermal and catalytic behavior of Ni-microsphere and Cu-MOF were investigated with aspartic acid as the coordinating ligand with different morphologies. The Ni-microsphere and Cu-MOF with aspartic acid, as the coordinating ligand, were prepared via a solvothermal method. The morphology and porosity of the obtained Ni microsphere and Cu-MOF were characterized by XRD, FTIR, TGA, DSC, BET and SEM techniques. The catalytic activity of the Ni-microsphere and Cu-MOF was examined in Stille and sulfoxidation reactions. The Ni microsphere and Cu-MOF were easily isolated from the reaction mixtures by simple filtration and then recycled four times without any reduction of catalytic efficiency.
- Ghorbani-Choghamarani, Arash,Bastan, Hosna,Kakakhani, Zahra,Taherinia, Zahra
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p. 14905 - 14914
(2021/05/19)
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- Lipids as versatile solvents for chemical synthesis
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Development of safe, renewable, cheap and versatile solvents is a longstanding challenge in chemistry. We show here that vegetable oils and related systems can become prominent solvents for organic synthesis. Suzuki-Miyaura, Hiyama, Stille, Sonogashira and Heck cross-couplings proceed with quantitative yields in a range of vegetable oils, fish oil, butter and waxes used as solvents. Appropriate methodologies for high-throughput screening and sustainable isolation techniques applicable for vegetable oils and related lipids are presented.
- Gevorgyan, Ashot,Hopmann, Kathrin H.,Bayer, Annette
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supporting information
p. 7219 - 7227
(2021/09/28)
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- N-Aroylsulfonamide-Photofragmentation (ASAP)-A Versatile Route to Biaryls
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The photochemical fragmentation of N-aroylsulfonamides 9 (ASAP) is a powerful method for the preparation of various biaryls. Compounds 9 are easily accessible in two steps from amines by treatment with arenesulfonyl chlorides and aroyl chlorides. Many of these compounds were prepared for the first time. The irradiation takes place in a previously developed continuous-flow reactor using inexpensive UVB or UVC fluorescent lamps. Isocyanates and sulphur dioxide are formed as the only by-products. The ASAP tolerates a variety of functional groups and is even suited for the preparation of phenylnaphthalenes and terphenyls. The ASAP mechanism was elucidated by interaction of photophysical and quantum chemical (DFT) methods and revealed a spirocyclic biradical as key intermediate.
- Wessig, Pablo,Krebs, Saskia
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supporting information
p. 6367 - 6374
(2021/09/29)
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- Radical Decarboxylative Carbometalation of Benzoic Acids: A Solution to Aromatic Decarboxylative Fluorination
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Abundant aromatic carboxylic acids exist in great structural diversity from nature and synthesis. To date, the synthetically valuable decarboxylative functionalization of benzoic acids is realized mainly by transition-metal-catalyzed decarboxylative cross couplings. However, the high activation barrier for thermal decarboxylative carbometalation that often requires 140 °C reaction temperature limits both the substrate scope as well as the scope of suitable reactions that can sustain such conditions. Numerous reactions, for example, decarboxylative fluorination that is well developed for aliphatic carboxylic acids, are out of reach for the aromatic counterparts with current reaction chemistry. Here, we report a conceptually different approach through a low-barrier photoinduced ligand to metal charge transfer (LMCT)-enabled radical decarboxylative carbometalation strategy, which generates a putative high-valent arylcopper(III) complex, from which versatile facile reductive eliminations can occur. We demonstrate the suitability of our new approach to address previously unrealized general decarboxylative fluorination of benzoic acids.
- Xu, Peng,López-Rojas, Priscila,Ritter, Tobias
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supporting information
p. 5349 - 5354
(2021/05/05)
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- Cobalt-Catalyzed Coupling of Aryl Chlorides with Aryl Boron Esters Activated by Alkoxides
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The cobalt-catalyzed Suzuki biaryl cross-coupling of aryl chloride substrates with aryl boron reagents, activated with more commonly used bases, remained a significant unmet challenge in the race to replace platinum group metal catalysts with Earth-abundant metal alternatives. We now show that this highly desirable process can be realized using alkoxide bases, provided the right counterion is employed, strict stoichiometric control of the base is maintained with respect to the aryl boron reagent, and the correct boron ester is selected. Potassium tert-butoxide works well, but any excess of the base first inhibits and then poisons the catalyst. Lithium tert-butoxide performs very poorly, while even catalytic amounts of lithium additives also poison the catalyst. Meanwhile, a neopentane diol-based boron ester is required for best performance. As well as delivering this sought-after transformation, we have undertaken detailed mechanistic and computational investigations to probe the possible mechanism of the reaction and help explain the unexpected experimental observations.
- Tailor, Sanita B.,Manzotti, Mattia,Smith, Gavin J.,Davis, Sean A.,Bedford, Robin B.
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p. 3856 - 3866
(2021/04/07)
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- Coupling of Reformatsky Reagents with Aryl Chlorides Enabled by Ylide-Functionalized Phosphine Ligands
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The coupling of aryl chlorides with Reformatsky reagents is a desirable strategy for the construction of α-aryl esters but has so far been substantially limited in the substrate scope due to many challenges posed by various possible side reactions. This limitation has now been overcome by the tailoring of ylide-functionalized phosphines to fit the requirements of Negishi couplings. Record-setting activities were achieved in palladium-catalyzed arylations of organozinc reagents with aryl electrophiles using a cyclohexyl-YPhos ligand bearing an ortho-tolyl-substituent in the backbone. This highly electron-rich, bulky ligand enables the use of aryl chlorides in room temperature couplings of Reformatsky reagents. The reaction scope covers diversely functionalized arylacetic and arylpropionic acid derivatives. Aryl bromides and chlorides can be converted selectively over triflate electrophiles, which permits consecutive coupling strategies.
- Hu, Zhiyong,Wei, Xiao-Jing,Handelmann, Jens,Seitz, Ann-Katrin,Rodstein, Ilja,Gessner, Viktoria H.,Goo?en, Lukas J.
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supporting information
p. 6778 - 6783
(2021/02/01)
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- Nickel(II) complexes with N,O-donor thiopseudourea ligands: Syntheses, structures, and catalytic applications in Kumada–Corriu cross-coupling reactions
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Synthesis, characterization, and physical properties of benzyl-N′-(4-R-benzoyl)-N-(2,6-diisopropylphenyl)carbamimidothioates, HL1 (R = H) and HL2 (R = Cl), and their nickel(II) complexes having the general molecular formula [Ni(L1/2)2] (1 and 2) have been reported. Elemental analysis, magnetic susceptibility, solution electrical conductivity, and various spectroscopic (IR, UV–Vis, and 1H NMR) measurements were used to characterize HL1, HL2, and the two complexes (1 and 2). The molecular structures of all four compounds were determined by single-crystal X-ray crystallographic studies. The structures of HL1 and HL2 showed the imino-ketone form of both compounds. In each of 1 and 2, the six-membered chelate ring forming iminolate-O and azomethine-N donor two (L1/2)? ligands form a square-planar trans-N2O2 coordination environment around the metal center. The spectroscopic characteristics of HL1, HL2, 1, and 2 are consistent with their molecular structures. Both complexes were successfully employed as efficient catalysts in Kumada–Corriu C-C cross-coupling reactions of aryl bromides with phenylmagnesium bromide. The reactions provided biaryl products in good to excellent yields with a good substrate scope.
- Shakunthala, Kinche,Srivastava, Ankit Kumar,Babu, G. Narendra,Keesara, Srinivas,Pal, Samudranil
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- Efficient photocatalytic chemoselective and stereoselective C-C bond formation over AuPd@N-rich carbon nitride
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Heterogeneous chemoselective or stereoselective C-C coupling reactions remain extremely challenging in traditional organic synthesis. Here, we constructed a AuPd@N-rich carbon nitride (NRCN) photocatalyst through simple ammonia solution heat treatment of carbon nitride and then AuPd NP loading. AuPd@NRCN exhibited extraordinary light color promoted catalytic performance in C-C bond formation under visible light in air. Surprisingly, both high chemoselectivity to unsymmetrical Ullmann biaryl products and satisfactory stereoselectivity to Z-type Heck reaction products could be achieved by changing the light source color. Various substrates exhibited great potential for the economical synthesis of unsymmetrical biaryl products and Z-type olefins. Efficient visible light promoted C-I bond activation accompanied with improved photocatalytic coupling reaction efficiency over AuPd@NRCN was verified firstly by in situ DRIFTS. Considering that the Ullmann cross-coupling reaction is a multi-photon reaction, the improved photocatalytic performance in the Ullmann cross-coupling reaction using a combination of light sources with different colors might be due to the activation of different substrates and/or steps requiring different energies, and the combination of the two energy sources was beneficial for improving the activation efficiency of different substrates and/or steps. The activation of iodobenzene and styrene in the Heck reaction with light was also beneficial to the formation of the stilbene product. The light color promoted chemoselectivity and stereoselectivity are expected to have profound impact on organic synthetic methodology improvement. This journal is
- Jiang, Heyan,Xu, Jie,Zhang, Sishi,Cheng, Hongmei,Zang, Cuicui,Bian, Fengxia
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p. 219 - 229
(2021/01/28)
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- Reductive Coupling of Aryl Halides via C—H Activation of Indene
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This paper describes the first case of a reductive coupling reaction with indene, a non-heteroatom olefin used as a reducing agent. The scope of the substrate is wide. The homo-coupling, cross-coupling, and synthesis of 12 and 14-membered rings were realized. The control experiment, indene-product curve and density functional theory calculations showed that the η3-palladium indene intermediate was formed by C—H activation in the presence of cesium carbonate. We speculate that the final product was obtained through a Pd (IV) intermediate or aryl ligand exchange. In addition, we excluded the formation of palladium anion (Pd(0)?) intermediates.
- Zhang, Bo-Sheng,Yang, Ying-Hui,Wang, Fan,Gou, Xue-Ya,Wang, Xi-Cun,Liang, Yong-Min,Li, Yuke,Quan, Zheng-Jun
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p. 1573 - 1579
(2021/05/28)
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- Porous Organic Phenanthroline-Based Polymer as an Efficient Transition-Metal-Free Heterogeneous Catalyst for Direct Aromatic C?H Activation
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Direct C?H bond transformation has been regarded as one of the most important areas in organic synthesis in both academia and industry. However, the heterogeneous transition-metal-free catalysis of direct C?H bond transformation has remained a contemporary challenge. To tackle this challenge, we designed and constructed a porous phenanthroline-based polymer (namely POP-Phen) via free radical polymerization of vinyl-functionalized phenanthroline monomers. POP-Phen shows excellent catalytic performances in transition-metal-free catalyzed C?H arylation, even better than those of the corresponding homogeneous catalyst, which is mainly attributed to the high density of catalytically active sites in the heterogeneous catalyst. Kinetic isotope experiments and spectral characterizations demonstrate the electron-transfer between the heterogeneous catalyst and the base (t-BuOK), a key step for C?H activation. We believe that this porous organic phenanthroline polymer could open a new door for the design of novel heterogeneous transition-metal-free catalysts for direct C?H activation.
- Tang, Yongquan,Chen, Fang,Wang, Sai,Sun, Qi,Meng, Xiangju,Xiao, Feng-Shou
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supporting information
p. 8684 - 8688
(2021/05/25)
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- Surface engineered Iridium-based magnetic photocatalyst paving a path towards visible light driven C-H arylation and cyanation reaction
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The report presents the fabrication and application of a highly versatile, magnetic and robust iridium based photoredox nanocatalyst. Herein, Ir(PPy)3 based photocatalyst sites have been chemically engineered over the magnetic nanoparticles to encompass the captivating features of homogeneous iridium photocatalyst with the magnetically recyclable core. A household photoreactor was designed and fabricated to achieve highly selective visible light driven oxidative C-H arylation and C-H cyanation under sustainable and ambient reaction conditions utilizing the Ir@PyBz@ASMNPs photoredox nanocatalyst. The environment friendly Ir@PyBz@ASMNPs shows excellent photocatalytic activity, broad substrate adaptability and outstanding recyclability compared to the analogous homogeneous catalysts. Indeed, the Ir@PyBz@ASMNPs possess some key features including high surface area, high iridium metal loading and excellent stability. This work is expected to enlighten and provide new insights in the rational design of high performance and recoverable photoredox nanocatalyst through surface engineering strategy.
- Gaur, Rashmi,Gawande, Manoj B.,Kaushik, Bhawna,Rana, Pooja,Sharma, Priti,Sharma, Rakesh K.,Yadav, Priya,Yadav, Sneha
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p. 297 - 308
(2021/08/23)
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- A new Pd(II)-supported catalyst on magnetic SBA-15 for C-C bond formation via the Heck and Hiyama cross-coupling reactions
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Magnetic mesoporous silica composite (MNP@SiO2-SBA) was obtained via embedding magnetite nanoparticles between SBA-15 channels. It was silylated with N-(3-(trimethoxysilyl)propyl)picolinamide (TMS-PCA) and then complexed with Pd(II). The obtained supported Pd(II) catalyst (MNP@SiO2-SBA-PCA) was characterized by conventional methods. The prepared magnetic catalyst showed high activity in the Heck and Hiyama reactions under optimal reaction conditions, including solvent, amount of catalyst, base, and temperature. Aryl bromides and iodides showed better results than aryl chlorides, and the catalyst exhibited noticeable stability and reused several times.
- Rahimi, Leila,Mansoori, Yagoub,Nuri, Ayat,Koohi-Zargar, Behzad,Esquivel, Dolores
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- Pd Nanoparticles Embedded Into MOF-808: Synthesis, Structural Characteristics, and Catalyst Properties for the Suzuki–Miyaura Coupling Reaction
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Abstract: A heterogeneous single-site catalyst Pd@MOF-808 was successfully synthesized by water-based, green synthesis procedure. The catalytic experiments exhibited the Pd@MOF-808 promoted efficiently the Suzuki–Miyaura coupling reaction without the assistance of organic phosphine ligands at atmospheric pressure conditions. The catalyst also could be applied in the gram-scale synthesis of industrially anti-inflanmatory analgestic Fenbufen. Graphic Abstract: [Figure not available: see fulltext.]
- Li, Tang,Pang, Wan,Wang, Jie,Zhang, Xiaoli,Zhao, Zesheng
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- Pd(II) complexes with ONN pincer ligand: Tailored synthesis, characterization, DFT, and catalytic activity toward the Suzuki-Miyaura reaction
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A pincer type ONN tridentate Schiff base ligand, 2-(((pyridin-2-yl)methylimino)methyl)-6-methoxyphenol, (L1) synthesized by the condensation of 4-hydroxy-3-methoxy-benzaldehyde and (pyridin-2-yl)methanamine. The ligand L1 and the new Pd(II) heteroleptic complexes of the composition [Pd(L1)(L2)]Cl, where L2 = benzimidazole, imidazole, benzooxazol or pyridine were synthesized and characterized by a set of chemical, spectrometric and spectroscopic analyses. These complexes were named 1 to 4, respectively. The FT-IR and DFT have suggested that ligand is coordinated with metal through azomethine-N and phenolic-O and arranged in square planar fashion around the metal. Correlation coefficients value between 0.995 - 0.993 shows satisfactory agreement in theoretical and experimental 1H-NMR and 13C-NMR. Benzimidazole anchored complex 1 exhibits an excellent catalytic activity. DFT calculated the energy profile diagram of the Suzuki-Miyaura reaction.
- Bagri, Sanjay Singh,Chaurasia, Bhaskar,Gaur, Pratiksha,Mehrotra, Ripul,Raidas, Mohan Lal,Shukla, Satyendra Nath
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- Polydopamine-Encapsulated Dendritic Organosilica Nanoparticles as Amphiphilic Platforms for Highly Efficient Heterogeneous Catalysis in Water
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Aqueous heterogeneous catalysis is a green, sustainable catalytic process that attracts increasing attention, but it often suffers from poor mass transfer, substrate adsorption and catalyst dispersion. Herein, we synthesized a type of amphiphilic core-shell catalysts with a hydrophilic polydopamine (PDA) shell and a hydrophobic dendritic organosilica nanoparticle (DON) core for heterogeneous catalysis in water. The hydrophilic shell allowed the catalyst dispersing well in water, and the hydrophobic core facilitated the absorption of organic reactants. The hierarchical core-shell structure facilitated rational arrangement of the location of catalytic species to match the reaction sequence. The obtained metal, enzyme and metal-enzyme amphiphilic catalysts demonstrated improved stability, selectivity and activity in aqueous reactions, including Pd-catalyzed cross-couplings (Suzuki, Liebeskind-Srogl, Heck and Sonogashira), enzymatic enantioselective reduction, chemoenzymatic cascade synthesis of chiral compounds and chemoenzymatic cascade degradation of organophosphates. The amphiphilic catalysts could be easily in situ recovered, and their high catalytic performance was sustained for five cycles.
- Gao, Jing,Guo, Na,Jiang, Yanjun,Liu, Guanhua,Liu, Pengbo,Liu, Yunting,Wang, Zihan,Zhang, Lei
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supporting information
p. 1975 - 1982
(2021/06/09)
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- Palladium nanoparticles immobilized on polyethylenimine-derivatized gold surfaces for catalysis of Suzuki reactions: Development and application in a lab-on-a-chip context
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Gold surface-bound hyperbranched polyethyleneimine (PEI) films decorated with palladium nanoparticles have been used as efficient catalysts for a series of Suzuki reactions. This thin film-format demonstrated good catalytic efficiency (TON up to 3.4 × 103) and stability. Incorporation into a quartz crystal microbalance (QCM) instrument illustrated the potential for using this approach in lab-on-a-chip-based synthesis applications.
- Anaspure, Prasad,Nicholls, Ian A.,Suriyanarayanan, Subramanian
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p. 35161 - 35164
(2021/11/30)
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- Selective C-O Bond Reduction and Borylation of Aryl Ethers Catalyzed by a Rhodium-Aluminum Heterobimetallic Complex
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We report the catalytic reduction of a C-O bond and the borylation by a rhodium complex bearing an X-Type PAlP pincer ligand. We have revealed the reaction mechanism based on the characterization of the reaction intermediate and deuterium-labeling experiments. Notably, this novel catalytic system shows steric-hindrance-dependent chemoselectivity that is distinct from conventional Ni-based catalysts and suggests a new strategy for selective C-O bond activation by heterobimetallic catalysis.
- Hara, Naofumi,Nakao, Yoshiaki,Saito, Teruhiko,Seki, Rin
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supporting information
p. 6388 - 6394
(2021/05/31)
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- Synthesis of N-Heterocyclic Carbine Silver(I) and Palladium(II) Complexes with Acylated Piperazine Linker and Catalytic Activity in Three Types of C—C Coupling Reactions
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Two bis-imidazolium salts LH2·Cl2 and LH2·(PF6)2 with acylated piperazine linker and two N-heterocyclic carbene (NHC) silver(I) and palladium(II) complexes [L2Ag2](PF6)2 (1) and [L2Pd2Cl4] (2) were prepared. The crystal structures of LH2·Cl2 and 1 were confirmed by X-ray analysis. In 1, one 26-membered macrometallocycle was generated through two silver(I) ions and two bidentate ligands L. The catalytic activity of 2 was investigated in Sonogashira, Heck-Mizoroki and Suzuki-Miyaura reactions. The results displayed that these C—C coupling reactions can be smoothly carried out under the catalysis of 2.
- Liu, Qingxiang,Zhang, Xiantao,Zhao, Zhixiang,Li, Xinying,Zhang, Wei
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supporting information
p. 605 - 613
(2021/02/01)
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- Agro-Waste Generated Pd/CAP-Ash Catalyzed Ligand-Free Approach for Suzuki–Miyaura Coupling Reaction
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Abstract: We converted agro-waste Custard Apple Peels (CAP) to ash via thermal treatment, on which Pd(OAc)2 was immobilized easily that produced a low-cost, highly efficient Pd/CAP-ash catalyst. The prepared catalyst was fully characterized by using FT-IR, SEM, EDX, XRF, DSC-TGA, BET, HR-TEM, and XPS techniques. The Pd/CAP-ash catalyst was conveniently applied for the Suzuki–Miyaura coupling reaction under external base free and ligand-free conditions in an aqueous-organic solvent to produce biphenyls in good to excellent yields. The main attraction of our protocol an application of palladium-supported agro-waste material which is easily recoverable and recyclable provides mono and bis-coupled derivatives in a short reaction time. Graphic Abstract: [Figure not available: see fulltext.].
- Patil, Rupesh C.,Jagdale, Ashutosh A.,Patil, Uttam P.,Ghodake, Jeevan S.,Mali, Sawanta S.,Hong, Chang K.,Patil, Suresh S.
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supporting information
p. 3617 - 3631
(2021/04/02)
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- Triptycene ring metal palladium compound and application thereof
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The invention discloses a triptycene cyclometalated palladium compound and an application thereof. The triptycene cyclometalated palladium compound has the following general formula, wherein three RAscan be the same or different and are respectively and independently expressed as R1-(Z1-A1-Z2)x-,wherein the three RBs can be the same or different and are respectively and independently expressed asR2-(Z3-A2-Z4)y-, the two RCs may be the same or different, each independently expressed as R3-(Z5-A3-Z6)z-. The triptycene cyclometalated palladium compound provided by the invention has a triptycenelarge-steric-hindrance group, and can stabilize a zero-valent palladium intermediate in a catalytic cycle, so that the catalytic efficiency is improved, the use amount of a catalyst can be reduced tobe less than ten thousandth, and the compound is simple in synthesis step, high in yield, relatively low in cost and suitable for various substrates, and the method has an important application valuefor researching the progress and application of the coupling reaction.
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-
Paragraph 0085-0092
(2021/02/24)
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- Biaryl compound as well as preparation method and application thereof
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The invention discloses a biaryl compound as well as a preparation method and application thereof. The preparation method comprises the following steps: reacting magnesium chips and lithium chloride in a schlenk sealed tube to obtain a reactant 1, adding ultra-dry tetrahydrofuran into the sealed tube, extracting nitrogen from the sealed tube, then adding aryl quaternary ammonium salt, a 5mol% catalyst, aryl bromide and N, N, N' N'-tetramethyldisiloxane, stirring and reacting at 25-60 DEG C for 6-12 hours to obtain a reactant 2, and finally, sequentially carrying out extracting, washing, drying, extract liquor removing and purifying on the reactant 2 to obtain the biaryl compound which can be used for preparing a compound containing a biaryl structure. The preparation method is wide in substrate range, convenient to operate, mild in reaction condition, low in pollution and high in economic benefit, and the obtained biaryl compound has good functional group tolerance and substrate universality.
- -
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Paragraph 0047-0055; 0057
(2021/09/21)
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- Supported phosphine free bis-NHC palladium pincer complex: An efficient reusable nanocatalyst for Suzuki-Miyaura coupling reaction
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A periodic mesoporous organosilica material functionalized with a bis-NHC palladium pincer complex was synthesized by sol-gel process. The resulting organic-inorganic hybrid nano material was characterized by XRD, TEM, SEM, TGA analysis, and BET measurements. The hybrid nanomaterial act as highly active catalysts for the Suzuki–Miyaura cross-coupling between deactivated aryl chlorides and phenylboronic acid under heterogeneous and aerobic conditions. The supported catalyst exhibited excellent activity and stability and it could be reused at least ten times without any significant loss of activity. Furthermore, the SEM image revealed that high order mesostructure of the recycled nanocatalyst. After ninth run, catalyst showed almost similar structure as compared to the fresh catalyst. ICP-AES detected no Pd contamination in the products, and leaching tests verified that the reaction was truly heterogeneous.
- Burange, Anand S.,Luque, Rafael,Rajabi, Fatemeh,Voskressensky, Leonid G.
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- An unsymmetrical Schiff-base derived recyclable Pd-catalyst for Suzuki–Miyaura and Sonogashira reactions in aqueous media
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Abstract: A water-soluble palladium (II) complex containing an unsymmetrical Schiff-base ligand was synthesized and applied as catalyst Suzuki–Miyaura and Sonogashira cross-coupling reactions in aqueous media. Notably, moderate to excellent yields of biaryls were obtained in Suzuki reaction with usually less reactive aryl and heteroaryl chlorides under relatively mild condition. Moderate-to-high yields of aryl-alkynes were also obtained in Sonogashira reactions using aryl bromides. Apart from hydrophilic nature, the accomplishment of reactions in water, high recyclability, broad functional group tolerance, etc., are other advantages of the system. Graphic abstract: [Figure not available: see fulltext.]
- Das, Pankaj,Gogoi, Achinta,Puzari, Amlan
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- Metal-free synthesis of biarenes via photoextrusion in di(tri)aryl phosphates
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A metal-free route for the synthesis of biarenes has been developed. The approach is based on the photoextrusion of a phosphate moiety occurring upon irradiation of biaryl- A nd triaryl phosphates. The reaction involves an exciplex as the intermediate and it is especially suitable for the preparation of electron-rich biarenes.
- Qrareya, Hisham,Meazza, Lorenzo,Protti, Stefano,Fagnoni, Maurizio
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supporting information
p. 3008 - 3014
(2021/01/18)
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- Kinetically Controlled Reticular Assembly of a Chemically Stable Mesoporous Ni(II)-Pyrazolate Metal-Organic Framework
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The application scope of metal-organic frameworks (MOFs) is severely restricted by their weak chemical stability and limited pore size. A robust MOF with large mesopores is highly desired, yet poses a great synthetic challenge. Herein, two chemically stable Ni(II)-pyrazolate MOFs, BUT-32 and -33, were constructed from a conformation-matched elongated pyrazolate ligand through the isoreticular expansion. The two MOFs share the same sodalite-type net, but have different pore sizes due to the network interpenetration in BUT-32. Controlled syntheses of the two MOFs have been achieved through precisely tuning reaction conditions, where the microporous BUT-32 was demonstrated to be a thermodynamically stable product while the mesoporous BUT-33 is kinetically favored. To date, BUT-32 represents the first example of Ni4-pyrazolate MOF whose structure was unambiguously determined by single-crystal X-ray diffraction. Interestingly, the kinetic product BUT-33 integrates 2.6 nm large mesopores with accessible Ni(II) active sites and remarkable chemical stability even in 4 M NaOH aqueous solution and 1 M Grignard reagent. This MOF thus demonstrated an excellent catalytic performance in carbon-carbon coupling reactions, superior to other Ni(II)-MOFs including BUT-32. These findings highlight the importance of kinetic control in the reticular synthesis of mesoporous MOFs, as well as their superiority in heterogeneous catalysis.
- He, Tao,Huang, Zhehao,Yuan, Shuai,Lv, Xiu-Liang,Kong, Xiang-Jing,Zou, Xiaodong,Zhou, Hong-Cai,Li, Jian-Rong
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supporting information
p. 13491 - 13499
(2020/09/02)
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- Decarbonylative Suzuki-Miyaura Cross-Coupling of Aroyl Chlorides
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Herein, we report a catalyst system for Pd-catalyzed decarbonylative Suzuki-Miyaura cross-coupling of aroyl chlorides with boronic acids to furnish biaryls. This strategy is suitable for a broad range of common aroyl chlorides and boronic acids. The synthetic utility is highlighted in the direct late-stage functionalization of pharmaceuticals and natural products capitalizing on the presence of carboxylic acid moiety. Extensive mechanistic and DFT studies provide key insight into the reaction mechanism and high decarbonylative cross-coupling selectivity.
- Zhou, Tongliang,Xie, Pei-Pei,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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supporting information
p. 6434 - 6440
(2020/09/02)
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- A one-pot protocol for the fluorosulfonation and Suzuki coupling of phenols and bromophenols, streamlined access to biaryls and terphenyls
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A one-pot protocol for the fluorosulfation and Suzuki coupling of phenols is described. The tandem reaction proceeds efficiently at room temperature, and various biaryls and biaryl fluorosulfates were obtained in good to excellent yields. Furthermore, biaryl fluorosulfates were utilized as versatile building blocks for the preparation of terphenyls. The Royal Society of Chemistry 2020.
- Hu, Rui,Li, Xinmin,Ren, Changyue,Yuan, Zeli,Zhang, Hang,Zhang, Tingting
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supporting information
p. 4748 - 4753
(2020/08/17)
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- Suzuki-Miyaura Cross-Coupling of Sulfoxides
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The utilization of diphenyl sulfoxides as versatile electrophilic coupling partners for the Suzuki-Miyaura reaction via C-S bond cleavage was successfully developed under palladium-N-heterocyclic carbene catalysis. The reactions showed good functional group compatibility, proceeded well under mild conditions, and provided biaryls in yields of up to 96%. A wide range of useful functional groups, such as fluoro, chloro, ether, hydroxyl, amide, cyano, keto, trimethylsilyl (TMS), and ester were tolerated under the reaction conditions; however, the use of phenylboronic anhydride and arylboronic acid pinacol esters generally would lead low yields. Good regioselectivity for the electron-poor phenyl group was achieved when unsymmetrical diphenyl sulfoxides were used. The protocol is applicable at the gram scale even with half the amount of catalyst. Density functional theory calculations were performed to investigate the reaction mechanism, indicating that the reaction occurred through oxidative addition, transmetalation, and reductive elimination to provide the final coupling product.
- Abduhulam, Hayrul,Cao, Changsheng,Chen, Qianwei,Dang, Yanfeng,Li, Chengxi,Shi, Yanhui,Wu, Shufeng,Yan, Shuqin
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p. 8168 - 8176
(2020/09/18)
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- Nickel(II)/N-Heterocyclic Carbene Catalyzed Desulfinylative Arylation by C?S Cleavage of Aryl Sulfoxides with Phenylboronic Acids
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Suzuki-Miyaura coupling of haloarenes is the most widely used protocol for the synthesis of biphenyls. Organosulfur compounds are promising electrophiles since they are abundant in nature and versatile in organic synthesis. We report here the desulfinylative Suzuki-Miyaura coupling of aryl sulfoxides with phenylboronic acids using bench-stable nickel/5-(2,4,6-triisopropylphenyl)imidazolylidene[1,5-a]pyridines as the catalyst. The ligands are readily prepared from common commercial chemicals. The method is applicable to both symmetric and unsymmetric aryl sulfoxides, and a range of biphenyls bearing various functional groups were obtained in up to 94% yield. (Figure presented.).
- Yi, Xiaowen,Chen, Kai,Guo, Junjun,Chen, Wei,Chen, Wanzhi
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supporting information
p. 4373 - 4377
(2020/07/27)
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- A Convoluted Polyvinylpyridine-Palladium Catalyst for Suzuki-Miyaura Coupling and C?H Arylation
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The development of highly active and reusable supported catalysts for Suzuki-Miyaura coupling and catalytic C?H arylation is important for fundamental and applied chemistry, with these reactions being used to produce medical compounds and functional materials. Herein, we found that a mesoporous composite made of a linear poly(4-vinylpyridine) and tetrachloropalladate acted as a dual-mode catalyst for a variety of cross-coupling reactions, with both Pd nanoparticles and a Pd complex catalyst being observed under different conditions. The polyvinylpyridine-palladium composite 1 was readily prepared via the molecular convolution of poly(4-vinylpyridine) and sodium tetrachloropalladate to provide a hardly soluble polymer-metal composite. The Suzuki-Miyaura coupling and the C?H arylation of aryl chlorides and bromides with arylboronic acids, thiophenes, furans, benzene, and anisole proceeded in the presence of 0.004 mol% (40 mol ppm) to 1 mol% Pd of 1 to afford the corresponding coupling products in high yields. Furthermore, the catalyst was reused without an appreciable loss of activity. Pharmaceutical compounds and functional materials were synthesized via the coupling reactions. N2 gas adsorption/desorption analysis indicated that the catalyst had a mesoporous nature, which played a crucial role in the catalysis. In the Suzuki-Miyaura couplings, in situ generated palladium nanoparticles in the polymer matrix were catalytically active, while a polymeric Pd(II) complex was crucial in the C?H arylations. These catalytic species were investigated via XAFS, XPS, far-infrared absorption, and Raman spectroscopies, as well as DFT calculations. (Figure presented.).
- Ohno, Aya,Sato, Takuma,Mase, Toshiaki,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
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supporting information
p. 4687 - 4698
(2020/09/07)
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- Small organic molecules with tailored structures: Initiators in the transition-metal-free C-H arylation of unactivated arenes
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Simple, small organic molecules containing nitrogen and oxygen atoms in their structures have been disclosed to catalyze transition-metal-free C-H arylation of unactivated arenes with aryl iodides in the presence of tBuOK. In this article, an optimized catalytically active molecule, (2-(methylamino)phenyl)methanol, was designed. A broad range of aryl iodides could be converted into the corresponding arylated products at 100 °C over 24 h with good to excellent yields. Mechanistic experiments verified that radicals participated in this catalytic transformation and that the cleavage of the aromatic C-H bond was not the rate determining step. A K+ capture experiment by 18-crown-6 emphasized the significance of the cation species of the strong base. Fourier transform infrared spectroscopy proved that the catalytic system was activated by the hydrogen bonds between small organic molecules and tBuOK. Also, a clear mechanism was proposed. This transition-metal-free method affords a promising system for efficient and inexpensive synthesis of biaryls via a user-friendly approach, as confirmed by scale-up experiments.
- Chen, Suqing,Chen, Wenjun,Chen, Yu,Liu, Zhenghui,Mu, Tiancheng,Wang, Peng,Yan, Zhenzhong
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p. 14500 - 14509
(2020/04/27)
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- Organocatalyst in Direct C(sp2)-H Arylation of Unactivated Arenes: [1-(2-Hydroxyethyl)-piperazine]-Catalyzed Inter-/Intra-molecular C-H Bond Activation
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This article describes the identification of 1-(2-hydroxyethyl)-piperazine as a new, cost-effective, highly efficient organocatalyst, which promotes both inter- A nd intra-molecular direct C(sp2)-H arylations of unactivated arenes in the presence of potassium tert-butoxide. While the inter-molecular C-H arylation of unactivated benzenes with aryl halides (Ar-X; X = I, Br, Cl) toward biaryl syntheses underwent smoothly in the presence of only 10 mol percent organocatalyst, the intra-molecular C-H arylation catalytic system composed of 40 mol percent each of the catalyst and the additive (4-dimethylaminopyridine (DMAP)). The novel catalyst was also able to perform both inter- A nd intra-molecular direct arylations simultaneously in a single pot. The mechanistic studies confirmed the involvement of aryl radical anions and proceeded via a single-electron-transfer (SET) mechanism. The large substrate scope, high functional group tolerance, competition experiments, gram-scale synthesis, and kinetic studies further highlight the importance and versatile nature of the methodology as well as the compatibility of the new catalyst. To the best of our knowledge, this is the first report on any organocatalyst that reported detailed investigations of both inter- A nd intra-molecular direct C(sp2)-H arylations of unactivated arenes in a single representation.
- Yadav, Lalit,Tiwari, Mohit K.,Shyamlal, Bharti Rajesh Kumar,Chaudhary, Sandeep
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p. 8121 - 8141
(2020/07/16)
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- An effective photothermal dual-responsive Pd1Cu4/Ce: XOy catalyst for Suzuki-Miyaura coupling reactions under mild conditions
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The Suzuki-Miyaura coupling reaction is one of the effective methods for forming C-C bonds in modern organic synthesis. However, most of the current catalysts can only effectively catalyze the aryl iodides and aryl bromides, and the catalytic activity for the inexpensive aryl chlorides is relatively low. Herein, the Pd1Cu4/CexOy catalysts can not only exhibit excellent performance in the conventional thermal reactions of aryl bromides and arylboronic acids, but also effectively activate aryl chlorides in Suzuki-Miyaura coupling reactions under visible light irradiation at room temperature. The CexOy carriers can provide photogenerated electrons to enrich the electron density of the Pd nanoparticles, which can effectively activate the strong C-Cl bonds of the aryl chlorides. Meanwhile, the photogenerated holes of CexOy can activate arylboronic acids. The presence of Pd and Cu2O can further enhance the absorption of visible light by CexOy. Catalysts prepared in this work could provide a great promise for using inexpensive metals to synergistically catalyze Suzuki-Miyaura coupling reactions under mild conditions.
- Liu, Bo,Xu, Tong,Li, Chunping,Bai, Jie
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p. 3794 - 3801
(2020/03/17)
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- L-lysine-Pd Complex Supported on Fe3O4 MNPs: a novel recoverable magnetic nanocatalyst for Suzuki C-C Cross-Coupling reaction
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In this work, L-lysine-Pd Complex, immobilized onto the surface of Fe3O4 MNPs, was successfully prepared via simple and inexpensive procedure. The prepared nanocatalyst was considered as a robust and clean nano-reactor catalyst for the Suzuki and Heck C-C Cross-Coupling reactions in water as the green condition. This eco-friendly heterogeneous catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), X-Ray Diffractometer (XRD), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma atomic emission spectroscopy (ICP), X-ray mapping, BET, thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) techniques. The use of a green medium, easy separation and workup, excellent reusability of the nanocatalyst and short reaction time are some outstanding advantages of this method.
- Ashraf, Muhammad Aqeel,Liu, Zhenling,Zhang, Dangquan,Alimoradi, Ashkan
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- Pd nanoparticles supported on Fe3O4@SiO2-Schiff base as an efficient magnetically recoverable nanocatalyst for Suzuki–Miyaura coupling reaction
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Abstract: In this work, Pd nanoparticles (Pd-NPs) were decorated on modified magnetic nanoparticles (MNPs) and used as an efficient and recyclable catalyst for the Suzuki cross-coupling reaction of aryl halides with phenylboronic acid (PhB(OH)2) in a green solvent. The prepared nanocomposite was characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Fourier transforms infrared spectroscopy, X-ray powder diffraction, thermogravimetric analysis/differential thermal analysis, and vibrating sample magnetometry. All analyses confirmed the successful modification of MNPs and immobilization of Pd on modified MNPs. This catalyst exhibited superior catalytic activity and stability in the suzuki cross-coupling reaction of PhB(OH)2 and aryl halide derivatives. This protocol includes some advantages, such as magnetically reusability of the catalyst, mild experimental conditions, green solvent, excellent yields of the product (52–98percent), and short reaction times (4–33?min). The catalyst could be reused for six successive runs without any significant loss of its efficiency. Graphic abstract: [Figure not available: see fulltext.]
- Amirmahani, Najmeh,Mahmoodi, Nosrat O.,Malakootian, Mohammad,Pardakhty, Abbas,Seyedi, Neda
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p. 4595 - 4609
(2020/08/05)
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- Palladium Supported on Silk Fibroin for Suzuki–Miyaura Cross-Coupling Reactions
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Silk fibroin supported Pd (Pd/SF) has been prepared and used as catalyst in Suzuki–Miyaura cross-coupling reactions in water/ethanol (4:1 v/v) mixture. The reactions proceed rapidly with aryl iodides and boronic acids with different electronic properties using low metal loading (0.38 mol-%). Pd/SF exhibits better recyclability compared to other biopolymer-supported Pd catalysts, up to nineteen cycles without loss of activity.
- Albano, Gianluigi,Farinola, Gianluca M.,Lo Presti, Marco,Milella, Antonella,Omenetto, Fiorenzo G.,Rizzo, Giorgio
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supporting information
p. 6992 - 6996
(2020/11/30)
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- Pd–ninhydrin immobilized on magnetic nanoparticles: synthesis, characterization, and application as a highly efficient and recoverable catalyst for Suzuki–Miyaura and Heck–Mizoroki C–C coupling reactions
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Abstract: In this work by controlling the interaction between the inorganic complexes and the support material, we have designed a high-activity nanostructured combined of magnetic nanoparticles and Pd–ninhydrin-terminated complex as catalyst. The as-prepared catalyst was characterized by FT-IR, XRD, VSM, SEM, EDAX, ICP, and TGA techniques. This magnetic nanostructure can be used as a novel, green, and efficient heterogeneous catalyst for Suzuki–Miyaura and Heck–Mizoroki C–C coupling reactions. This catalyst showed promising catalytic activity and excellent yields toward various aryliodides and arylbromides in mild reaction conditions. In Suzuki–Miyaura reactions, various aryl halides (I, Br) were coupled with phenyl boronic acids in 5?mg of catalyst and 8?mg of catalyst used for Mizoroki–Heck reaction of aryl halides (I, Br) with n-butyl acrylate or acrylonitrile. The catalyst was reusable and recycled six times without a significant loss in activity and leaching of palladium. Graphic abstract: [Figure not available: see fulltext.].
- Hajjami, Maryam,Shirvandi, Zeinab
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p. 1059 - 1072
(2020/01/06)
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- L-Methionine-Pd complex supported on hercynite as a highly efficient and reusable nanocatalyst for C-C cross-coupling reactions
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A "green" method was suggested for the synthesis of hercynite magnetic nanoparticles (MNPs) as a novel heterogeneous catalytic support to immobilize homogeneous complexes. l-Methionine-Pd was immobilized on the surface of hercynite MNPs by a simple, rapid, and convenient route. The structure and composition of the prepared Hercynite@l-Methionine-Pd MNPs were characterized by X-ray diffraction spectroscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectrometry, scanning electron microscopy, X-ray mapping, thermogravimetric analysis and vibrating-sample magnetometry (VSM). Besides, they were applied as green nanocatalysts for Suzuki and Heck cross-coupling reactions. Hercynite@l-Methionine-Pd MNPs offer several advantages (simple synthetic method under green conditions, thermal and chemical stability during organic reactions, short reaction times, high yields of products, excellent selectivity and easy work-up procedure). Moreover, the recycled nanocatalyst was reused for at least five cycles with no significant loss of activity. The hot filtration test indicated heterogeneous catalysis for Suzuki and Heck cross-coupling reactions. This work is useful for the development and application of a magnetically recoverable Pd nanocatalyst on the basis of green-chemistry principles.
- Mohammadi, Masoud,Ghorbani-Choghamarani, Arash
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supporting information
p. 2919 - 2929
(2020/03/03)
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