- Zeolitic imidazolate frameworks-67 (ZIF-67) supported PdCu nanoparticles for enhanced catalytic activity in Sonogashira-Hagihara and nitro group reduction under mild conditions
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A bimetallic PdCu supported on amine functionalized ZIF-67 is shown to be efficient catalyst in Sonogashira-Hagihara coupling reaction of aryl iodides at room temperature and aryl bromides at 40 oC. In addition, the catalyst is used in the reduction of 4-
- Gholinejad, Mohammad,Naghshbandi, Zhwan,Sansano, Jose M.
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- A Waste-Minimized Approach to Cassar-Heck Reaction Based on POLITAG-Pd0 Heterogeneous Catalyst and Recoverable Acetonitrile Azeotrope
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Three different Pd0-based heterogeneous catalysts were developed and tested in the Cassar–Heck reaction (i. e., copper-free Sonogashira reaction) aiming at the definition of a waste minimized protocol. The cross-linked polymeric supports used in this investigation were designed to be adequate for different reaction media and were decorated with different pincer-type ionic ligands having the role of stabilizing the formation and dimension of palladium nanoparticles. Among the ionic tags tested, bis-imidazolium showed the best performances in terms of efficiency and durability of the metal catalytic system. Eventually, aqueous acetonitrile azeotrope was selected as the reaction medium as it allowed the best catalytic efficiency combined with easy recovery and reuse. Finally, the synergy between the selected catalyst and reaction medium allowed to obtain highly satisfactory isolated yields of a variety of substrates while using a low amount of metal catalyst. The high performance of the designed POLymeric Ionic TAG (POLITAG)-Pd0, along with its good selectivity achieved in a copper-free process, also led to a simplified purification procedure allowing the minimization of the waste generated as also proven by the very low E-factor values (1.4–5) associated.
- Valentini, Federica,Ferlin, Francesco,Tomarelli, Elena,Mahmoudi, Hamed,Bagherzadeh, Mojtaba,Calamante, Massimo,Vaccaro, Luigi
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p. 3359 - 3366
(2021/07/28)
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- Xantphos-coordinated palladium dithiolates: Highly efficient catalyst for decarboxylative Sonogashira reaction into corresponding alkynes
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This work reports Xantphos-coordinated palladium dithiolate complexes as catalysts for decarboxylative Sonogashira coupling reaction of phenyl propiolic acid and 2-butynoic acid with various iodoarenes. These palladium aryl dithiolate complexes were synthesized and characterized by 1H and 31P nuclear magnetic resonance (NMR) spectroscopy, melting point, and elemental analysis (CHNS). Synthetic utility for the reported protocol is explored for the effect of various functional groups on the yield of corresponding heteroaryl alkynes. The current protocol showed excellent catalytic activity towards decarboxylative alkynylation reaction with high turn-over number (TON) up to 105 and turn-over frequency (TOF) up to 104 h?1. The catalyst could be recycled up to six recycles without losing its catalytic activity. The in situ generation of palladium nanoparticles (PdNPs) was observed after the third recycle, and the amount was significant after the sixth recycle, which were confirmed and characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray (EDX) analysis and high-resolution transmission electron microscopy (HR-TEM). The catalytic activity of the reaction is attributed to the formation of PdNPs.
- Lokolkar, Manjunath S.,Mane, Pravin A.,Dey, Sandip,Bhanage, Bhalchandra M.
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- Simple and efficient diaryl alkyne synthesis method
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The embodiment of the invention discloses a simple and efficient diaryl alkyne synthesis method. The method comprises the steps of by taking arylmethylbenzotriazole and aromatic aldehyde as raw materials, carrying out addition and double-beta-elimination reaction under the action of bis (trimethylsilyl) amino salt MN (SiMe3) 2 to synthesize diaryl alkyne by a one-pot method. The raw materials and chemical reagents used in the method are easy to obtain, the reaction conditions are mild, the operation is simple, the substrate universality is good, the product yield is high, and the method is a simple and efficient diaryl alkyne synthesis method.
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Paragraph 0026; 0029-0031
(2021/04/14)
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- Highly efficient synthesis of 1,2-disubstituted acetylenes derivatives from the cross-coupling reactions of 1-bromoalkynes with organotitanium reagents
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A Highly efficient route for the synthesis of 1,2-disubstituted acetylene derivatives has been developed by nickel catalyzed cross-couplings of alkynyl halides with aryl titanium reagents under mild conditions. This has given corresponding cross-coupling products good to excellent isolated yields of up to 92 %. The aryls bearing electron-donating or electron-withdrawing groups in either alkynylhalides or aryltitanium substrates gave cross-coupling products good yields. This process was simple and easily performed, which provides an efficient method for the synthesis of 1,2-disubstituted acetylenes derivatives.
- Li, Qing-Han,Wu, Chuan
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supporting information
(2021/08/25)
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- Highly Efficient Synthesis of 2-Substituted Benzo[ b ]furan Derivatives from the Cross-Coupling Reactions of 2-Halobenzo[ b ]furans with Organoalane Reagents
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A highly efficient and simple route for the synthesis of 2-substituted benzo[ b ]furans has been developed by palladium-catalyzed cross-coupling reaction of 2-halobenzo[ b ]furans with aryl, alkynyl, and alkylaluminum reagents. Various 2-aryl-, 2-alkynyl-, and 2-alkyl-substituted benzo[ b ]furan derivatives can be obtained in 23-97% isolated yields using 2-3 mol% PdCl 2/4-6 mol% XantPhos as the catalyst under mild reaction conditions. The aryls bearing electron-donating or electron-withdrawing groups in 2-halobenzo[ b ]furans gave products in 40-97% isolated yields. In addition, aluminum reagents containing thienyl, furanyl, trimethylsilanyl, and benzyl groups worked efficiently with 2-halobenzo[ b ]furans as well, and three bioactive molecules with 2-substituted benzo[ b ]furan skeleton were synthesized. Furthermore, the broad substrates scope and the typical maintenance of vigorous efficiency on gram scale make this protocol a potentially practical method to synthesize 2-substituted benzo[ b ]furan derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed.
- Wen, Chang,Wu, Chuan,Luo, Ruiqiang,Li, Qinghan,Chen, Feng
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p. 3847 - 3861
(2021/07/02)
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- Decarbonylative Sonogashira Cross-Coupling of Carboxylic Acids
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Decarbonylative Sonogashira cross-coupling of carboxylic acids by palladium catalysis is presented. The carboxylic acid is activated in situ by the formation of a mixed anhydride and further decarbonylates using the Pd(OAc)2/Xantphos system to provide an aryl-Pd intermediate, which is intercepted by alkynes to access the traditional Pd(0)/(II) cycle using carboxylic acids as ubiquitous and orthogonal electrophilic cross-coupling partners. The methodology efficiently constructs new C(sp2)-C(sp) bonds and can be applied to the derivatization of pharmaceuticals. Mechanistic studies give support to decarbonylation preceding transmetalation in this process.
- Liu, Chengwei,Szostak, Michal
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supporting information
p. 4726 - 4730
(2021/06/28)
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- Facile one-pot synthesis of diarylacetylenes from arylaldehydes: Via an addition-double elimination process
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A practical one-pot protocol has been developed to synthesize diarylacetylenes from arylaldehydes by treatment with 1-(arylmethyl)benzotriazoles and LiN(SiMe3)2. The reaction proceeded through imine formation, Mannich-type addition and double elimination to deliver products in up to 99% yields with broad substrate scope. In addition, gram-scale synthesis of 1-bromo-4-(phenylethynyl)benzene has been demonstrated.
- Chen, Jianyang,Zhang, Xuan,Wu, Jiajun,Wang, Rui,Lei, Chunlin,An, Yanan
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p. 4701 - 4705
(2021/06/11)
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- Selective Phosphoranation of Unactivated Alkynes with Phosphonium Cation to Achieve Isoquinoline Synthesis
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We herein develop a selective phosphoranation of alkynes with phosphonium cation, which directs a concise approach to isoquinolines from unactivated alkyne and nitrile feedstocks in a single step. Mechanistic studies suggest that the annulation reaction is initiated by the unprecedented phosphoranation of alkynes, thus representing a unique reaction pattern of phosphonium salts and distinguishing it from existing protocols that largely rely on the utilization of highly functionalized imines/oximes and/or highly polarized alkynes.
- Cui, Hong,Bai, Jinku,Ai, Tianyu,Zhan, Ye,Li, Guanzhong,Rao, Honghua
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supporting information
p. 4023 - 4028
(2021/05/26)
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- Ligand-Promoted Alkynylation of Aryl Ketones: A Practical Tool for Structural Diversity in Drugs and Natural Products
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Conversion of the numerous aryl ketones into aryl electrophiles via Ar-C(O) cleavage remains a challenging yet highly desirable transformation in Sonogashira-type coupling. Herein, we report a palladium-catalyzed ligand-promoted alkynylation of unstrained aryl ketones. The protocol allows the alkynylation to be carried out in a one-pot procedure with broad functional-group tolerance and substrate scope. The potential applications of this protocol in drug discovery and chemical biology are further demonstrated by late-stage diversification of a number of pharmaceuticals and natural products. More importantly, two different biologically important fragments derived from a pharmaceutical and natural product could be connected by the consecutive alkynylation of ketones. Distinct from aryl halides in conventional Sonogashira reactions, the protocol provides a practical tool for the 1,2-bifunctionalization of aryl ketone by merging ketone-directed ortho-C-H activation with ligand-promoted ipso-Ar-C(O) alkynylation.
- Xu, Hui,Ma, Biao,Fu, Zunyun,Li, Han-Yuan,Wang, Xing,Wang, Zhen-Yu,Li, Ling-Jun,Cheng, Tai-Jin,Zheng, Mingyue,Dai, Hui-Xiong
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p. 1758 - 1764
(2021/02/09)
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- Designing Homogeneous Copper-Free Sonogashira Reaction through a Prism of Pd-Pd Transmetalation
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Simultaneous introduction of two different palladium (pre)catalysts, one tuned to promote oxidative addition to (hetero)aryl bromide and another to activate terminal alkyne substrate, leads to productive Pd-Pd transmetalation, subsequent reductive elimina
- Martek, Bruno A.,Gazvoda, Martin,Urankar, Damijana,Ko?mrlj, Janez
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supporting information
p. 4938 - 4943
(2020/05/19)
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- Fast heck-cassar-sonogashira (hcs) reactions in green solvents
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The replacement of toxic solvents with greener alternatives in Heck-Cassar-Sonogashira (HCS) cross-couplings was investigated. The fine-tuning of the HCS protocol allowed to achieve complete conversions and high speed under mild conditions. N-Hydroxyethylpyrrolidone (HEP) gave the best results. Moreover, the methodology was successfully applied to the synthesis of an intermediate of the anticancer drug Erlotinib, demonstrating the versatility of the new green protocol.
- Cabri, W.,Corbisiero, D.,Daka, A.,Fantoni, T.,Ferrazzano, L.,Martelli, G.,Ricci, A.,Tolomelli, A.,Viola, A.
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supporting information
p. 3969 - 3973
(2020/06/08)
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- Sustainable Ligand-Free Heterogeneous Palladium-Catalyzed Sonogashira Cross-Coupling Reaction in Deep Eutectic Solvents
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The commercially available and cheap Pd/C was found to promote Sonogashira couplings in the environmentally friendly choline chloride/glycerol eutectic mixture in the absence of external ligands. Under heterogeneous conditions, (hetero)aryl iodides were successfully coupled with both aromatic and aliphatic alkynes in yields ranging from 50 to 99 % within 3 h at 60 °C. The aforementioned catalytic system proved to be effective also towards electron-rich iodides, which are notoriously known to be poorly reactive in Pd-catalyzed Sonogashira coupling reactions. The eutectic mixture and the catalyst could easily and successfully be recycled up to four times with an E-factor as low as 24.4.
- Messa, Francesco,Dilauro, Giuseppe,Perna, Filippo M.,Vitale, Paola,Capriati, Vito,Salomone, Antonio
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p. 1979 - 1984
(2020/02/20)
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- A Simple Nickel Catalyst Enabling an E-Selective Alkyne Semihydrogenation
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Stereoselective alkyne semihydrogenations are attractive approaches to alkenes, which are key building blocks for synthesis. With regards to the most atom-economic reducing agent dihydrogen (H2), only few catalysts for the challenging E-selective alkyne semihydrogenation have been disclosed, each with a unique substrate scope profile. Here, we show that a commercially available nickel catalyst facilitates the E-selective alkyne semihydrogenation of a wide variety of substituted internal alkynes. This results in a simple and broadly applicable overall protocol to stereoselectively access E-alkenes employing H2, which could serve as a general method for synthesis.
- Thiel, Niklas O.,Kaewmee, Benyapa,Tran Ngoc, Trung,Teichert, Johannes F.
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supporting information
p. 1597 - 1603
(2020/02/05)
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- Hybrid hydrogels loaded with palladium nanoparticles – Catalysts for environmentally-friendly Sonogashira and Heck cross-coupling reactions
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Palladium nanoparticles (PdNPs) were encapsulated within hybrid hydrogels made from an acylhydrazide-functionalised 1,3:2,4-dibenzylidene sorbitol (DBS-CONHNH2) low-molecular-weight gelator (LMWG) combined with agarose polymer gelator via in situ reduction of Pd(II). These heterogeneous gel-phase catalysts were successfully applied for copper-, amine- and phosphine-free Sonogashira cross-coupling reactions under environmentally-friendly conditions without the need for inert atmosphere reaction conditions. The PdNP-loaded gel was reused in Sonogashira couplings up to at least five times with no adverse effect on yield. The performance of solvated PdNP-loaded gel catalysts was compared with the dried xerogels. The xerogels can be used at higher temperatures, enhancing reaction kinetics albeit lowering reaction selectivity, but unlike the solvated gels, were unable to be easily recycled and reused. The PdNP-loaded gels also had good activity in Heck reactions, and although longer reaction times or higher temperatures were required than for the Sonogashira reaction, the reaction conditions were mild for a Heck coupling. In summary, we demonstrate a ‘waste-to-wealth’ methodology in which Pd(II) ‘waste’ is converted into a valuable gel-phase catalyst that can be used for green Sonogashira and Heck cross-coupling reactions.
- Slavik, Petr,Smith, David K.
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- A Bithiophene-Promoted ppm Levels of Palladium-Catalyzed Regioselective Hydrosilylation of Terminal Allenes
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A bithiophene?alkyne-based compound was synthesized and first utilized as a ligand for the selective hydrosilylation of allenes with primary and secondary phenylsilanes. It shows high selectivity towards the production of branched allylsilanes with a wide range of allenes. It is worth mentioning that the catalytic loading of the palladium can be reduced to 500 ppm. This work opens a new front of using bidentate thiophene ligand as a reaction promoter in transition-metal-catalyzed organic reaction. (Figure presented.).
- Chen, Jun-Jia,Zeng, Jia-Hao,Yang, Ying,Liu, Zhi-Kai,Jiang, Ya-Nan,Li, Miao-Ran,Chen, Li,Zhan, Zhuang-Ping
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p. 2360 - 2366
(2020/04/28)
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- Encapsulating palladium nanoparticles inside ethylenediamine functionalized and crosslinked chlorinated poly(vinyl chloride) nanofibers as an efficient and stable heterogeneous catalyst for coupling reactions
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Palladium chloride and chlorinated poly (vinyl chloride) (CPVC) mixture were prepared into homogeneous solution, followed by electrospinning to make uniform nanofibers with average diameter of ~460 nm. Then, these composite nanofibers were treated in ethy
- Du, Yijun,Qi, Chenze,Qin, Min,Shao, Linjun,Tao, Hongyu,Wang, Qingqing
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- Benzimidazolyl Palladium Complexes as Highly Active and General Bifunctional Catalysts in Sustainable Cross-Coupling Reactions
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A family of air- A nd moisture-stable dinuclear palladium complexes bearing 2-benzimidazolyl ligands is reported and shown to be a highly effective and general catalytic platform in diverse cross-coupling reactions. The rigidity and conformation of the ligand scaffold was readily modified via tethering of the 2-benzimidazolyl moiety to diamine ligands, resulting in significant changes in catalytic activity. Under optimal conditions, Suzuki, Heck, and Sonogashira-type couplings of aryl bromides can all be performed efficiently with good functional group compatibility using only 0.1 mola?% of catalyst, in aqueous or alcohol solvents. Experimental evidence highlights the importance of the bifunctional character of the ligand for catalytic activity, where the basic N-functionality in the ligand framework is proposed to accelerate (trans)metalation steps via intramolecular assistance.
- Zhu, Jiancheng,Lindsay, Vincent N. G.
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p. 6993 - 6998
(2019/08/26)
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- Gold-Catalyzed Oxidation of Internal Alkynes into Benzils and its Application for One-Pot Synthesis of Five-, Six-, and Seven-Membered Azaheterocycles
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Internal alkynes have been shown to undergo oxidation to substituted benzils (1,2-diarylethane-1,2-diones) by α-picoline N-oxide in the presence of Ph3PAuNТf2 (5 mol-%). In addition to the unsubstituted benzil, the method allows preparing, under markedly mild conditions (50 °C in chlorobenzene), various non-symmetrical products, including heteroaromatic versions thereof which are much more difficult to obtain otherwise. This gold(I)-catalyzed transformation was integrated into one-pot reaction sequence delivering a range of 5- to 7-membered ring systems (imidazoles, quinoxalines, 1,2,4-triazines, pyrazines, and 1,4-diazepines), thus linking these important heterocyclic motifs to the internal alkyne reagent space.
- Dubovtsev, Alexey Yu.,Dar'in, Dmitry V.,Krasavin, Mikhail,Kukushkin, Vadim Yu.
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supporting information
p. 1856 - 1864
(2019/02/19)
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- Sustainable dipolar homo-dicopper (II) dihydrazone complex as a catalyst for Sonogashira cross couplings
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A novel dicopper (II) complex, Cu2L, was prepared form the complexation of the new polydentate ligand (H4L), bis(sodium 3-formyl-4-hydroxybenzenesulfonate)succinylhydrazone, with copper acetate. The novel homobinuclear complex was quite characterized by various physico-chemical tools and employed as a homogeneous and efficient-green catalyst for Sonogashira cross-couplings of phenylacetylene with halobenzenes under sustainable conditions. Cu2L exhibited very good catalytic performance with excellent chemoselectivity. The catalytic efficiency of Cu2L was improved by using ionic liquids–aqueous media (1: 1, binary mixture). A mechanistic pathway was also proposed for Cu(II)-catalyzed Sonogashira cross-coupling reactions for the reported finding. DFT for H4L and Cu2L were studied. Electronic configurations, energy of HOMO and LUMO orbitals, energy gap between orbitals (ΔE), electronegativity, hardness and softness were also calculated and compared with the applicable catalytic findings of Cu2L, which are in good conformity.
- Adam, Mohamed Shaker S.
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- Continuous flow solvent free organic synthesis involving solids (reactants/products) using a screw reactor
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Here we report for the first-time various organic transformations such as aldol condensation, oxidation, nucleophilic substitutions, protection, acylations and coupling reactions using a mechanochemical approach at a controlled temperature using a single synthesis platform. Almost minimal solvents or solvent-free conditions are used, making it a very efficient and clean synthesis of various products. A jacketed screw reactor when operated at different temperatures (0 °C to 160 °C) and over a range of rotation speeds for changing the residence time (15 s-300 s) helped to achieve maximum conversion. This approach is also extended to the synthesis using substrates having different substitutions, heterocycles and steric hindrance.
- Sharma, Brijesh M.,Atapalkar, Ranjit S.,Kulkarni, Amol A.
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supporting information
p. 5639 - 5646
(2019/10/22)
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- Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids
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It was demonstrated that the γ-valerolactone-based ionic liquid, tetrabutylphosphonium 4-ethoxyvalerate as a partially bio-based solvent can be utilized as alternative reaction medium for copper- and auxiliary base-free Pd-catalyzed Sonogashira coupling reactions of aryl iodides and functionalized acetylenes under mild conditions. Twenty-two cross-coupling products were isolated with good to excellent yields (72–99%) and purity (>98%). These results represent an example which proves that biomass-derived safer solvents can be utilized efficiently in common, industrially important transformations exhibiting higher chemical and environmental efficiency.
- Orha, László,Tukacs, József M.,Kollár, László,Mika, László T.
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supporting information
p. 2907 - 2913
(2019/12/14)
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- A Bipyridine-Palladium Derivative as General Pre-Catalyst for Cross-Coupling Reactions in Deep Eutectic Solvents
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A versatile and DES-compatible bipyridine palladium complex has been developed as a general pre-catalyst for different cross-coupling reactions (Hiyama, Suzuki-Miyaura, Heck-Mizoroki and Sonogashira) in deep eutectic solvents. Hydrogen bond capacity of the ligand allows to keep the excellent level of results previously obtained in classical organic solvents. Palladium pre-catalyst showed a high catalytic activity for many cross-coupling reactions, demonstrating a great versatility and applicability. Also, this methodology employs sustainable solvents as a reaction medium and highlights the potential of DES as alternative solvents in organometallic catalysis. The catalyst and DES were easily and successfully recycled. The formation of PdNPs in DES has been confirmed by TEM and XPS analysis and their role as catalyst by mercury test. The dynamic coordination of bipyridine-type ligand in the palladium complex formation has been studied via UV/Vis. (Figure presented.).
- Saavedra, Beatriz,González-Gallardo, Nerea,Meli, Alessandro,Ramón, Diego J.
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supporting information
p. 3868 - 3879
(2019/07/12)
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- Proton-Coupled Electron Transfer: Transition-Metal-Free Selective Reduction of Chalcones and Alkynes Using Xanthate/Formic Acid
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Highly chemoselective reduction of α,β-unsaturated ketones to saturated ketones and stereoselective reduction of alkynes to (E)-alkenes has been developed under a transition-metal-free condition using a xanthate/formic acid mixture through proton-coupled electron transfer (PCET). Mechanistic experiments and DFT calculations support the possibility of a concerted proton electron-transfer (CPET) pathway. This Birch-type reduction demonstrates that a small nucleophilic organic molecule can be used as a single electron-transfer (SET) reducing agent with a proper proton source.
- Prasanna, Ramanathan,Guha, Somraj,Sekar, Govindasamy
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supporting information
p. 2650 - 2653
(2019/04/17)
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- Sequentially Pd/Cu-Catalyzed Alkynylation-Oxidation Synthesis of 1,2-Diketones and Consecutive One-Pot Generation of Quinoxalines
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We report a simple and efficient one-pot synthesis of 1,2-diketones by concatenation of two Pd/Cu-catalyzed processes: Pd0/CuI-catalyzed Sonogashira coupling of terminal alkynes with aryl (pseudo)halides furnishes internal alkynes, which are directly transformed by PdII/CuII-catalyzed Wacker-type oxidation with DMSO and oxygen as dual oxidants to furnish 1,2-diketones. With this efficient, catalyst economical process, various aryl iodides and triflates are efficiently transformed in high yields into symmetrically and unsymmetrically substituted 1,2-diketones with various functional groups. This process can be readily extended to a consecutive one-pot synthesis of quinoxalines in a diversity-oriented fashion.
- Niesobski, Patrik,Martínez, Ivette Santana,Kustosz, Sebastian,Müller, Thomas J. J.
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supporting information
p. 5214 - 5218
(2019/07/31)
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- Visible Light-Catalyzed Decarboxylative Alkynylation of Arenediazonium Salts with Alkynyl Carboxylic Acids: Direct Access to Aryl Alkynes by Organic Photoredox Catalysis
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A convenient method mediated by photoredox catalysis is developed for the direct construction of aryl alkynes. Readily available aromatic diazonium salts have been utilized as the aryl radical source to couple alkynyl carboxylic acids to feature the decarboxylative arylation. A wide range of substrates are amenable to this protocol with broad functional group tolerance, and diversely-functionalized aryl alkynes could be synthesized under mild, neutral and transition metal-free reaction conditions using visible light irradiation. Alongside synthetic sustainability associated with the photocatalytic and transition metal-free operation, another key point of this method is that the organic dye catalyst acts as an excited-state reductant, thus establishing the quenching cycle for radical addition and decarboxylative elimination. (Figure presented.).
- Yang, Liangfeng,Li, Haifeng,Du, Yijun,Cheng, Kai,Qi, Chenze
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p. 5030 - 5041
(2019/11/03)
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- Cobalt catalyzed stereodivergent semi-hydrogenation of alkynes using H2O as the hydrogen source
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Cobalt-catalyzed stereodivergent semi-hydrogenation of internal alkynes to alkenes is developed. The reaction proceeded through transfer hydrogenation under mild conditions using a base metal CoI2 as the catalyst, and H2O/MeOH as the hydrogen source with Zn as the reductant. The E/Z-selectivity of the product could be switched by changing the solvent and by inclusion/exclusion of a bidentate phosphine ligand (dppe). This method provides a simple and cost effective pathway for the synthesis of 1,2-dideuterioalkenes.
- Li, Kangkui,Khan, Ruhima,Zhang, Xuexin,Gao, Yang,Zhou, Yongyun,Tan, Heng,Chen, Jingchao,Fan, Baomin
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supporting information
p. 5663 - 5666
(2019/05/21)
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- Preparation method of aryl alkyne catalyzed by visible light
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The invention discloses a simple and convenient method for directly synthesizing an aryl alkyne compound through photoredox catalysis. Aryl fluoroborate diazoate is used as an aryl free radical source, and different types of aryl alkyne are synthesized in situ through a decarboxylation process. A reaction has good functional group tolerability, and a simple domestic visible light source can be used for synthesizing the aryl alkyne of different functional groups under mild, neutral and transition-free metal reaction conditions.
- -
-
Paragraph 0050-0053
(2019/11/13)
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- Self-assembly of catalytically active supramolecular coordination compounds within metal?organic frameworks
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Supramolecular coordination compounds (SCCs) represent the power of coordination chemistry methodologies to self-assemble discrete architectures with targeted properties. SCCs are generally synthesized in solution, with isolated fully coordinated metal atoms as structural nodes, thus severely limited as metal-based catalysts. Metal?organic frameworks (MOFs) show unique features to act as chemical nanoreactors for the in situ synthesis and stabilization of otherwise not accessible functional species. Here, we present the self-assembly of PdII SCCs within the confined space of a pre-formed MOF (SCCs@MOF) and its post-assembly metalation to give a PdII?AuIII supramolecular assembly, crystallography underpinned. These SCCs@MOFs catalyze the coupling of boronic acids and/or alkynes, representative multi-site metal-catalyzed reactions in which traditional SCCs tend to decompose, and retain their structural integrity as a consequence of the synergetic hybridization between SCCs and MOFs. These results open new avenues in both the synthesis of novel SCCs and their use in heterogeneous metal-based supramolecular catalysis.
- Adam, Rosa,Mon, Marta,Greco, Rossella,Kalinke, Lucas H.G.,Vidal-Moya, Alejandro,Fernandez, Antonio,Winpenny, Richard E.P.,Domenech-Carbo, Antonio,Leyva-Perez, Antonio,Armentano, Donatella,Pardo, Emilio,Ferrando-Soria, Jesus
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supporting information
p. 10350 - 10360
(2019/08/20)
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- Self-Assembly of Catalytically Active Supramolecular Coordination Compounds within Metal-Organic Frameworks
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Supramolecular coordination compounds (SCCs) represent the power of coordination chemistry methodologies to self-assemble discrete architectures with targeted properties. SCCs are generally synthesized in solution, with isolated fully coordinated metal atoms as structural nodes, thus severely limited as metal-based catalysts. Metal-organic frameworks (MOFs) show unique features to act as chemical nanoreactors for the in situ synthesis and stabilization of otherwise not accessible functional species. Here, we present the self-assembly of PdII SCCs within the confined space of a pre-formed MOF (SCCs?MOF) and its post-assembly metalation to give a PdII-AuIII supramolecular assembly, crystallography underpinned. These SCCs?MOFs catalyze the coupling of boronic acids and/or alkynes, representative multi-site metal-catalyzed reactions in which traditional SCCs tend to decompose, and retain their structural integrity as a consequence of the synergetic hybridization between SCCs and MOFs. These results open new avenues in both the synthesis of novel SCCs and their use in heterogeneous metal-based supramolecular catalysis.
- Adam, Rosa,Mon, Marta,Greco, Rossella,Kalinke, Lucas H. G.,Vidal-Moya, Alejandro,Fernandez, Antonio,Winpenny, Richard E. P.,Doménech-Carbó, Antonio,Leyva-Pérez, Antonio,Armentano, Donatella,Pardo, Emilio,Ferrando-Soria, Jesús
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supporting information
p. 10350 - 10360
(2019/08/27)
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- Sonogashira Cross-Coupling of Aryltrimethylammonium Salts
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A protocol for C(sp)-C(sp2) bond formation via the Sonogashira coupling reaction involving C-N bond cleavage with aryltrimethylammonium triflate as an electrophilic coupling partner is described in this work. The reactions proceeded well under mild conditions with a stoichiometric ratio of alkyl, aryl, or heteroaryl acetylenes and provided yields of up to 93%. Numerous useful functional groups were tolerated under the reaction conditions. Direct amine alkynylation can be achieved through a one-pot process without the isolation of ammonium salt. The protocol can be performed on a gram scale. Density functional theory calculations were performed to investigate the reaction mechanism that involved oxidative addition, alkyne coordination, deprotonation, and reductive elimination, which yielded the cross-coupling product.
- Chen, Qianwei,Gao, Fengchen,Tang, Huiling,Yao, Miao,Zhao, Qian,Shi, Yanhui,Dang, Yanfeng,Cao, Changsheng
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p. 3730 - 3736
(2019/04/13)
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- Magnetically retrievable N-heterocyclic carbene-silver complex with wingtip ferrocenyl group for Sonogashira coupling
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A new magnetically retrievable N-heterocyclic carbene-silver complex with wingtip ferrocenyl group has been prepared by multi-step procedure. The formation of complex was confirmed on the basis of analytical techniques such as FT-IR, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-Ray diffraction (XRD), transmission electron microscopy (TEM) and VSM (vibrating sample magnetometer) analysis. The complex was successfully employed as an efficient heterogeneous catalyst for Sonogashira coupling reaction of aryl halides with terminal alkynes. The complex could be separated easily by applying external magnet. The reusability studies revealed that complex can be reused up to eight times without significant decrease in catalytic activity.
- Naikwade, Altafhusen,Bansode, Prakash,Rashinkar, Gajanan
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p. 112 - 122
(2018/05/03)
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- Novel oxime-palladacycle supported on clay composite as an efficient heterogeneous catalyst for Sonogashira reaction
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A novel supported catalyst formed by an oxime-derived palladacycle supported on clay OxPdCy@clay is synthesized and characterized. This palladium composite promotes the Sonogashira reaction of aryl iodides, bromides and chlorides with terminal alkynes in polyethylene glycol200 at 85 or 130 °C using 0.05–0.1 mol% of palladium loading under copper and phosphine free conditions. This supported palladacycle, OxPdCy@clay, showed a superior catalytic activity than dimeric oxime-palladacycles. Mechanistic studies about the heterogeneous or homogeneous nature of the catalyst show that catalyst is working mainly under heterogeneous conditions. This supported palladacycle OxPdCy@clay can be recycled by simple centrifugation and reused for at least nine consecutive runs with small decrease in activity.
- Gholinejad, Mohammad,Dasvarz, Neda,Nájera, Carmen
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p. 262 - 270
(2018/09/06)
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- Recyclable cellulose-palladium nanoparticles for clean cross-coupling chemistry
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Cheap, recyclable, and robust cellulose-palladium nanoparticles were developed and fully characterized by FTIR, TEM, XPS, TGA, and NMR. The nanoparticles enabled cross-coupling chemistry in a truly general fashion i.e., Suzuki-Miyaura, Heck, Sonogashira, and C-H activation. Notably, all types of transformations were achieved with a single type of nanocatalyst. Complete recyclability of the catalyst and low traces of palladium in the product demonstrates the greenness of the protocol.
- Lu, Zhichao,Jasinski, Jacek B.,Handa, Sachin,Hammond, Gerald B.
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supporting information
p. 2748 - 2752
(2018/04/27)
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- Heterogenized Cu (II) salen complex grafted on graphene oxide nanosheets as a precursing catalyst for the Pd-free Sonogashira coupling
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Cu (II) salen complex immobilized on graphene oxide nanosheets [Cu (II) salen@GO] was synthesized with 3-chloropropyltrimethoxysilan as a linker and wholly characterized using various techniques like X-ray diffraction, Fourier-transform infrared, scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy, as well as atomic absorption spectroscopy (AAS). Cu (II) salen@GO as an effective heterogeneous catalyst has been investigated for the Sonogashira coupling reaction in dimethylsulfoxide with good to high yield (98%) in 4?hr at 110°C when the loading of Cu was 0.7?mmol?g?1 based on Cu element analysis by AAS. It was understood that heterogeneous catalyst was as active as its homogeneous analog, and presented good recoverability and no significant loss in activity within successive runs.
- Ghabdian, Mahdieh,Nasseri, Mohammad A.,Allahresani, Ali,Motavallizadehkakhky, Alireza
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- Sonogashira-type cross-coupling reactions catalyzed by copper complexes of pincer N-heterocyclic carbenes
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Copper complexes of N-heterocyclic carbenes (NHC) have recently received great attention in catalysis, however, the application scope has been limited to neutral complexes bearing monodentate ligands. Herein, we report the synthesis and full characterization of a cationic Cu-pincer bis(NHC) complex with bulky tert-butyl wingtips that serves as catalyst for the coupling of aryl iodides and phenylacetylene, alongside its analogs with small alkyl substituents. Unlike other copper catalysts that require an inert atmosphere to prevent alkyne homocoupling, a competing side reaction to Sonogashira reaction, the Cu-pincer bis(NHC) complexes provide good to excellent cross-coupling yields in air. Interestingly, the reaction under argon affords substantially reduced cross-coupling, indicative of the oxygen involvement and its facilitating effect in the mechanism. In our controlled studies, the air-assisted cross-coupling reaction came to a complete stop when using a radical trap, suggesting the presence of a radical in the mechanism. Examining the reaction of Cu-pincer bis(NHC) complexes with oxygen via UV–vis spectroscopy reveals a dark green chromophore formation at ?40 °C with strong absorbance (ε > 400 M?1cm?1) at 460 nm and 500 nm, likely due to a high-valent copper-oxygen adduct.
- Domyati, Doaa,Latifi, Reza,Tahsini, Laleh
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supporting information
p. 98 - 105
(2018/03/06)
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- Transition-Metal-Free Highly Chemoselective and Stereoselective Reduction with Se/DMF/H2O System
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A novel metal-free reduction system, in which H2Se (or HSe-) produced in situ from Se/DMF/H2O acts as the active reducing species, has been developed. By using water as an inexpensive, safe, and environmentally friendly surrogate as the hydrogen donor, this new reduction system incorporating Se/DMF/H2O displayed high selectivity and good activity in the reduction of α,β-unsaturated ketones and alkynes. Therefore, this reduction system has great potential to be a general and practical reduction methodology in organic transformation.
- Li, Hong-Chen,An, Cui,Wu, Ge,Li, Guo-Xing,Huang, Xiao-Bo,Gao, Wen-Xia,Ding, Jin-Chang,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
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supporting information
p. 5573 - 5577
(2018/09/12)
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- Highly efficient synthesis of 1,2-disubstituted acetylenes derivatives from the cross-coupling reactions of 1-bromoalkynes with organoalane reagents
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A Highly efficient route for the synthesis of 1,2-disubstituted acetylene derivatives has been developed by palladium catalyzed cross-couplings of alkynyl halides with (hetero)aryl aluminium reagents under mild conditions. This has given corresponding cross-coupling products good to excellent isolated yields of up to 99%. The aryls bearing electron-donating or electron-withdrawing groups in either alkynylhalides or arylaluminum substrates gave cross-coupling products good yields. This process was simple and easily performed, which provides an efficient method for the synthesis of 1,2-disubstituted acetylenes derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed.
- Shao, Xue-Bei,Jiang, Xin,Li, Qing-Han,Zhao, Zhi-Gang
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p. 6063 - 6070
(2018/09/12)
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- Alkyne compound and synthesis method and application thereof
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The invention relates to the field of organic synthesis, in particular to an alkyne compound and a synthesis method and application thereof. The invention discloses a method for synthesizing an alkynecompound, which comprises the following steps: allowing a compound in formula (II) and a compound in formula (III) to react in the presence of an inert solvent under the action of catalyst and oxidizing agent to obtain a compound in formula (I). The synthesis method has simple and easily available materials, safe and simple operation, wide application range of substrate and good selectivity, doesn't need pre-activating, and is easily involved in free radical reaction, and byproducts are nitrogen and water, which conforms to sustainable green chemistry. The alkyne compound obtained by the above synthesis method is a brand-new alkyne compound, and the alkyne compound can be widely used in the fields of medicine and materials, and solves the technical problems of high cost, low stability andcomplication of alkyne compound synthesis reaction in the prior art.
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Paragraph 0073-0075
(2018/12/13)
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- Catalytic Activation of Trimethylsilylacetylenes: A One-Pot Route to Unsymmetrical Acetylenes and Heterocycles
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For the synthesis of unsymmetrical acetylenes, a Sonogashira coupling-deprotection-Sonogashira coupling reaction sequence is often used. Removal of protecting groups requires harsh conditions or an excess of difficult to handle and expensive reagents. Herein, we disclose a novel catalytic method for the selective deprotection of trimethylsilylacetylenes in Sonogashira reaction. The reagent hexafluorosilicic acid, an inexpensive nontoxic compound, was used to promote the selective desilylation. This method enables the efficient synthesis of unsymmetric acetylenes with other silylated functional groups present. Further possibilities of the method were explored by synthesis of heterocycles.
- Lasányi, Dániel,Mészáros, ádám,Novák, Zoltán,Tolnai, Gergely L.
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p. 8281 - 8291
(2018/06/11)
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- Phosphinito palladium(ii) complexes as catalysts for the synthesis of 1,3-enynes, aromatic alkynes and ynones
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An air-stable phosphinito palladium(ii) complex (Ph1-Phoxide) has been found to be an efficient catalyst in the formation of C-C bonds. The coupling of terminal alkynes formed gem-1,3-enynes as the only reaction products. Aromatic alkynes can be synthesized from the coupling of terminal alkynes and haloaromatic compounds (Sonogashira coupling). The phosphinito palladium(ii) complex also catalyses the coupling between acyl chlorides and terminal alkynes (Sonogashira coupling), furnishing ynones in excellent yields.
- Islas,Cárdenas,Gavi?o,García-Ríos,Lomas-Romero,Morales-Serna
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p. 9780 - 9789
(2017/02/15)
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- Palladium stabilized on poly and mono sulfonamide ligands as novel, simple, effective, and recyclable nano catalysts for C-C cross-coupling reactions
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Poly and mono sulfonamide ligands were successfully used for the stabilization of palladium nanoparticles. The prepared nano catalysts that appeared to be heterogeneous and novel were characterized with various analytical tools. To establish the catalytic activity of the prepared catalysts, they were used in the Suzuki-Miyaura and Sonogashira-Hagihara coupling reactions of aryl halides under low palladium loading conditions. The catalysts showed good stability and could be recovered and reused for seven reaction cycles without significant loss of catalytic activity.
- Ghorbani-Vaghei, Ramin,Sarmast, Narges
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p. 1073 - 1080
(2017/10/03)
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- Ligand- and copper-free Sonogashira and Heck couplings of (Het)aryl chlorides and bromides catalyzed by palladium nanoparticles supported on in situ generated Al(OH)3
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The ligand- and copper-free Sonogashira reaction of (Het)aryl halides (Br and Cl) with various terminal alkynes and the Heck coupling of (Het)aryl halides (Br and Cl) with a series of olefins, catalyzed by palladium nanoparticles supported on newly generated Al(OH)3, were developed. The catalyst can be readily recovered and reused 6 times without significant loss of activity and palladium leaching.
- Li, Xing,Gong, Xiaolei,Li, Zhipeng,Chang, Honghong,Gao, Wenchao,Wei, Wenlong
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p. 2475 - 2479
(2017/02/05)
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- Deep Eutectic Solvent Compatible Metallic Catalysts: Cationic Pyridiniophosphine Ligands in Palladium Catalyzed Cross-Coupling Reactions
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Cationic pyridiniophosphine ligands have been synthetized in an attempt to develop a deep eutectic solvents (DESs) compatible catalytic systems. These ligands, in combination with PdCl2, have been successfully applied to different palladium-catalyzed cross coupling reactions, such as Suzuki–Miyaura, Sonogashira, or Heck couplings. While traditional palladium ligands in DES medium failed to reproduce the results obtained in VOC solvents, these cationic phosphines improved the catalytic activity of palladium as no other traditional ligand could in such a polar medium. In addition, the recyclability of these processes was studied, allowing us to reuse both, catalyst and solvent up to 5 times in Suzuki and Sonogashira reactions without a significant drop in the catalytic activity. Regarding the structure of the Pd catalysts, titration, NMR, and DFT studies have clearly demonstrated the coordination properties of the DES-compatible cationic phosphine ligands.
- Marset, Xavier,Khoshnood, Abbas,Sotorríos, Lia,Gómez-Bengoa, Enrique,Alonso, Diego A.,Ramón, Diego J.
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p. 1269 - 1275
(2017/04/14)
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- Hydrophenoxylation of internal alkynes catalysed with a heterobimetallic Cu-NHC/Au-NHC system
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A straightforward method for the hydrophenoxylation of internal alkynes, using N-heterocyclic carbene-based copper(i) and gold(i) complexes, is described. The heterobimetallic catalytic system proceeds via dual activation of the substrates to afford the d
- Lazreg, Fa?ma,Guidone, Stefano,Gómez-Herrera, Alberto,Nahra, Fady,Cazin, Catherine S. J.
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supporting information
p. 2439 - 2444
(2017/03/08)
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- Sonogashira (Cu and amine free) and Suzuki coupling in air catalyzed: Via nanoparticles formed in situ from Pd(ii) complexes of chalcogenated Schiff bases of 1-naphthaldehyde and their reduced forms
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The reaction of 1-naphthaldehyde with 2-(phenylthio/seleno)ethylamine afforded air- and moisture-insensitive Schiff bases: C10H7-1-CHN-CH2CH2EPh (L1: E = S; L2: E = Se). Then, on treatment with NaOAc and Li2PdCl4, palladacycles, [Pd(L1-H/L2-H)Cl] (1/2) were formed at room temperature, in which L1/L2 are ligated as an unsymmetric (C-, N, E) pincer. The reduction of >CN bonds of L1 and L2 with sodium borohydride gave C10H7-1-CH2NH-CH2CH2EPh (L3: E = S; L4: E = Se). The reactions of L3/L4 at room temperature, similar to those of L1/L2, resulted in the formation of complex [Pd(L3/L4)Cl2] (3/4), in which the ligand is coordinated in a bidentate (N, E) mode. The yield of all the complexes was >85%. Characterization by HR-MS, 1H, 13C{1H} and 77Se{1H} NMR spectra of L1-L4 and their complexes 1-4 were performed. The structures of L1 and 1-4 were established with single-crystal X-ray diffraction. In all the complexes, the geometry of palladium was distorted square planar. The Pd-S bond distances in 1 and 3 were 2.426(12) and 2.259(2) ?, respectively, whereas Pd-Se bond lengths (?) were 2.523(11) (2) and 2.369(10) (4) ?. The catalytic activities of 1-4 were explored for copper- and amine-free Sonogashira and Suzuki-Miyaura coupling (SMC) of aryl halides under aerobic conditions. The amount of catalyst required for achieving good conversion was 0.01 and 0.05 mol% for SMC and Sonogashira coupling, respectively. The conversion of some substrates reached a maximum in 1 and 2 h for Sonogashira coupling and SMC, respectively. The palladacycles as catalysts gave good conversion efficiency. The generation of palladium-containing nanoparticles (NPs) during both coupling reactions was observed. These were isolated and HR-TEM studies were performed on them and revealed their size as ~2-7 nm. The SEM-EDX analysis indicated the presence of organochalcogen ligands or their fragments in the samples. They independently catalyzed both reactions. Therefore, the role of 1-4 in catalysis undoubtedly exists. For Sonogashira coupling, the formation and role of such Pd-based NPs under aerobic conditions were observed for the first time. The complexes 1-4 showed the potential for reuse, as in the eighth cycle, conversion dropped by only 20%.
- Bhaskar, Renu,Sharma, Alpesh K.,Yadav, Manoj K.,Singh, Ajai K.
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p. 15235 - 15248
(2017/11/22)
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- Three Different Reactions, One Catalyst: A Cu(I) PNP Pincer Complex as Catalyst for C-C and C-N Cross-Couplings
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An air-stable, thermally robust, and well-defined Cu(I) PNP pincer complex based on the 2,6-diaminopyridine scaffold is described. This complex is an active catalyst for the cross-couplings of a range of aryl and heteroaryl (including benzoxazole, thiazole, pyridine, and thiophene) halides with different organomagnesium reagents, alkynes, and aryl-amines giving excellent to good isolated yields.
- Mastalir, Matthias,Pittenauer, Ernst,St?ger, Berthold,Allmaier, Günter,Kirchner, Karl
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supporting information
p. 2178 - 2181
(2017/04/28)
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- N, N -Dimethylformamide-stabilized copper nanoparticles as a catalyst precursor for Sonogashira-Hagihara cross coupling
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We report the catalysis of a Sonogashira-Hagihara cross-coupling reaction using a DMF-stabilized copper nanoparticle catalyst. The reaction proceeded with low catalyst loadings, and a turnover number of 4.0 × 103 was recorded for 0.01 mol% cata
- Oka, Hideo,Kitai, Katsuya,Suzuki, Takeyuki,Obora, Yasushi
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p. 22869 - 22874
(2017/07/10)
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- Recyclable and eco-friendly Pd-complexed graphene oxide/N-heterocyclic carbene catalyst for various coupling reactions in aqueous phase
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In this study, we report recyclable Pd-complexed graphene oxide (GO) catalysts with a bulky N-heterocyclic carbene (NHC) ligand (GO/NHC-Pd) for various cross-coupling reactions in the aqueous phase. To prepare GO/NHC-Pd, the NHC precursor and a trimethoxy-silane linker were combined on the GO surface via condensation, followed by the Pd chelation over GO/NHC. The GO-based catalysts were applied to three types of C–C cross-coupling reactions including Suzuki, Heck and Sonogashira reactions in the aqueous phase, to evaluate their catalytic performance. The reusability of the catalysts was tested by performing five consequent cross-coupling reactions.
- Kim, Seongsoo,Cho, Hong-Jun,Shin, Dong-Sik,Lee, Sang-Myung
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supporting information
p. 2421 - 2425
(2017/05/31)
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- Thiophene-Alkyne-Based CMPs as Highly Selective Regulators for Oxidative Heck Reaction
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Thiophenes containing an adjacent C≡C group as ligands for PdII-promoted organic reactions are reported for the first time. These ligands were utilized as catalytic sites and integrated into the skeleton of conjugated microporous polymers. By e
- Li, Ren-Hao,Ding, Zong-Cang,Li, Cun-Yao,Chen, Jun-Jia,Zhou, Yun-Bing,An, Xiao-Ming,Ding, Yun-Jie,Zhan, Zhuang-Ping
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supporting information
p. 4432 - 4435
(2017/09/11)
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