- Organozinc-mediated direct cross-coupling under microwave irradiation
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We report a direct cross-coupling reaction between (het)aryl pivalates/tosylates and di(het)arylzinc species in 2-methyltetrahydrofuran/N-methyl pyrrolidone (1:1), which occurs via C–O bond cleavage under microwave irradiation. The reaction takes place smoothly in short reaction times without the addition of any catalyst or ligand. The reaction is suitable for a broad scope of substrates and exhibits good functional group compatibility, utilizes a simple work-up procedure, and gives the desired products in high purity.
- Li, Chun-Jing
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p. 869 - 875
(2021/07/02)
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- Catalytic SNAr Hydroxylation and Alkoxylation of Aryl Fluorides
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Nucleophilic aromatic substitution (SNAr) is a powerful strategy for incorporating a heteroatom into an aromatic ring by displacement of a leaving group with a nucleophile, but this method is limited to electron-deficient arenes. We have now established a reliable method for accessing phenols and phenyl alkyl ethers via catalytic SNAr reactions. The method is applicable to a broad array of electron-rich and neutral aryl fluorides, which are inert under classical SNAr conditions. Although the mechanism of SNAr reactions involving metal arene complexes is hypothesized to involve a stepwise pathway (addition followed by elimination), experimental data that support this hypothesis is still under exploration. Mechanistic studies and DFT calculations suggest either a stepwise or stepwise-like energy profile. Notably, we isolated a rhodium η5-cyclohexadienyl complex intermediate with an sp3-hybridized carbon bearing both a nucleophile and a leaving group.
- Kang, Qi-Kai,Li, Ke,Li, Yuntong,Lin, Yunzhi,Shi, Hang,Xu, Lun
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supporting information
p. 20391 - 20399
(2021/08/13)
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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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- A general palladium-catalyzed cross-coupling of aryl fluorides and organotitanium (IV) reagents
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Pd(OAc)2/1-[2-(di-tert-butylphosphanyl)phenyl]-4-methoxy-piperidine was demonstrated to effectively catalyze cross-coupling of aryl fluoride and aryl(alkyl) titanium reagent. Both electron-deficient and electron-rich aryl fluoride can react effectively with nucleophile and provide extensive functional groups tolerance. 2-Arylated product was realized by selective activation of the C–F bond. Graphic abstract: [Figure not available: see fulltext.].
- He, Xiao-Yun
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p. 823 - 832
(2021/07/19)
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- Aerobic Cu and amine free Sonogashira and Stille couplings of aryl bromides/chlorides with a magnetically recoverable Fe3O4@SiO2 immobilized Pd(II)-thioether containing NHC
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Two value added C–C cross coupling reactions; Sonogashira and Stille couplings were achieved at milder conditions in the catalytic presence of a magnetically recoverable heterogeneous catalyst Fe3O4@SiO2@NHC^SPh-Pd(II). The catalyst was earlier reported for Suzuki-Miyaura reaction, and as an extension of its catalytic efficiency, the Stille and Sonogashira cross coupling reactions under aerobic condition has been explored in present report. The Sonogashira coupling of aryl bromides and terminal alkynes produced an excellent yield (~96% at 0.25 mol% Pd) of the desired coupling product under copper and amines free conditions. Moreover, an excellent Stille coupling of readily available and more latent aryl chlorides and trialkylstannane was obtained (yields up to 95% at 0.25 mol% Pd) in absence of toxic fluorides additives. The broad substrate scope of the catalyst for both the coupling reactions and the magnetically recoverable feature of catalyst make this reaction highly desirable for industrial applications of present heterogeneous catalysis.
- Khandaka, Himanshu,Sharma, Kamal Nayan,Joshi, Raj Kumar
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supporting information
(2021/02/20)
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- Fabrication of Graphitic Carbon Nitride-Based Film: An Emerged Highly Efficient Catalyst for Direct C—H Arylation under Solar Light
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Photoredox C—H bond formation can proceed in aerobic environment under solar light and has therefore become attractive. Nowadays, different types of expensive novel metal complexes and nanomaterials have been urbanized as photocatalysts for direct C—H bon
- Chaubey, Surabhi,Yadav, Rajesh K.,Kim, Tae Wu,Yadav, Tara Chand,Kumar, Abhishek,Dwivedi,Pandey,Singh, Atul P.
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p. 633 - 639
(2021/02/12)
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- Pyrazole-Mediated C-H Functionalization of Arene and Heteroarenes for Aryl-(Hetero)aryl Cross-Coupling Reactions
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Herein we introduce a transition-metal-free protocol that involves a commercially available, inexpensive pyrazole molecule to conduct C-C cross-coupling reactions at room temperature via a radical pathway. Using this method, an aryldiazonium salt has been coupled to a wide range of arenes and heteroarenes including benzene, mesitylene, thiophene, furan, benzoxazole to result the corresponding biaryl products. The full reaction mechanism is elucidated along with the crystallographic probation of an active initiator species. A potassium-stabilized deprotonated pyrazole steers single-electron transfer to the substrate and behaves as an initiator for the reaction.
- Kundu, Abhishek,Dey, Dhananjay,Pal, Subhankar,Adhikari, Debashis
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p. 15665 - 15673
(2021/11/16)
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- Synthesis of Enaminone-Pd(II) Complexes and Their Application in Catalysing Aqueous Suzuki-Miyaura Cross Coupling Reaction
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A series of Pd(II)-enaminone complexes, termed Pd(eao)2, have been synthesized and characterized. The investigation on the catalytic activities of these new Pd(II)-reagents has proved that the Pd(eao)2-1 possesses excellent catalytic activity for the Suzuki- Miyaura cross coupling reactions of aryl bromides/chlorides with aryl/vinyl boronic acids in the environmentally benign media of aqueous PEG400 at low loading (5 mol‰). The superiority of this Pd(II)-reagent to those commercial Pd(II) and Pd(0) catalysts in catalyzing the reactions has been confirmed by parallel experiments. What's more, Pd(eao)2-2 has been found as a practical catalyst for the homo-coupling reactions of aryl boronic acids.
- Fu, Leiqing,Cao, Xiaoji,Wan, Jie-Ping,Liu, Yunyun
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p. 254 - 258
(2020/01/25)
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- Water-soluble cyclic tetra-nuclear palladium (II) complex as well as preparation method and application thereof
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The invention discloses a water-soluble palladium coupling catalyst-water-soluble cyclic tetra-nuclear palladium (II) complex as well as a preparation method and application thereof. The activity of acatalytic coupling reaction is preliminarily evaluated.
- -
-
Paragraph 0028-0041
(2020/07/15)
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- Synthesis of Novel Benzothiophene Derivatives via Cyclization Reactions
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Abstract: The Sonogashira cross coupling reaction of 2-bromo-5-(4-methoxyphenyl)thiophene and 1-ethynyl-2-(methylsulfanyl)benzene gave 2-(4-methoxyphenyl)-5-{[2-(methylsulfanyl)phenyl]ethynyl}thiophene which was subjected to electrophilic cyclization by t
- Algso, M. A. S.,Hama, A. K.,Kavak, E.,Kivrak, A.
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p. 1272 - 1278
(2020/09/17)
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- A facile synthesis of mesoporous graphitic carbon nitride supported palladium nanoparticles as highly effective and reusable catalysts for Stille coupling reactions under mild conditions
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The development of a Stille coupling protocol that is operable under moderate conditions without using a base is highly required for the synthetic organic chemistry community, which requires an efficient nanocatalyst. In this respect, addressed herein is a facile one-pot synthesis of mesoporous graphitic carbon nitride (mpg-CN) supported Pd NPs, denoted as mpg-CN/Pd hereafter, and investigation of their catalytic activity in Stille cross-coupling reactions for the first time. It has been demonstrated that mpg-CN nanosheets can serve as not only a support material but also a stabilizer for the generation of 4.5 nm Pd NPs. The ecofriendly generated heterogeneous nanocatalyst was characterized by TEM, XRD, XPS, BET surface area and ICP-MS analysis. The mpg-CN/Pd nanocatalysts showed high activity in the Stille coupling reaction of a variety of electron-deficient and electron-rich aryl iodides/bromides and two different organostannanes with a wide substrate scope to afford the corresponding biaryls without using any bases and additional ligands under relatively mild conditions. The catalyst can be easily recovered from the reaction medium by centrifugation. It can be reused at least 5 times without any loss of activity.
- Cetin, Sultan,Kalay, Erbay,Kolemen, Safacan,Metin, ?nder
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p. 6714 - 6723
(2020/05/16)
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- Air-Stable Fe3O4@SiO2-EDTA-Ni(0) as an Efficient Recyclable Magnetic Nanocatalyst for Effective Suzuki-Miyaura and Heck Cross-Coupling via Aryl Sulfamates and Carbamates
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The synthesis of inexpensive and novel air-stable Ni(0) nanoparticles immobilized on the EDTA-modified Fe3O4@SiO2 nanocatalyst was investigated in Suzuki-Miyaura and Heck cross-coupling reactions. This catalytic system displayed a greatly improved substrate scope for the carbon–carbon bond formations starting from a wide range of green and economical electrophiles aryl and heteroaryl carbamates and sulfamates via highly efficient method under mild, operationally simple reaction conditions. The synthesized heterogeneous catalyst was also fully characterized by FT-IR, TEM, XRD, DLS, FE-SEM, UV–Vis, EDX, XPS, TGA, NMR, VSM, ICP and elemental analysis techniques. The heterogeneous magnetic nanocatalyst can easily be recovered by an external magnetic field and reused for the next reactions for at least seven times with negligible leaching of catalyst and no substantial decrement in the activity. All these highlights have made the present protocol an interesting, simple and environmentally benign process with low catalyst loading and easy manipulations.
- Dindarloo Inaloo, Iman,Majnooni, Sahar,Eslahi, Hassan,Esmaeilpour, Mohsen
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- Transition-Metal-Free Synthesis of Heterobiaryls through 1,2-Migration of Boronate Complex
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The synthesis of a diverse range of heterobiaryls has been achieved by a transition-metal-free sp2–sp2 cross-coupling strategy using lithiated heterocycle, aryl or heteroaryl boronic ester and an electrophilic halogen source. The construction of heterobiaryls was carried out through electrophilic activation of the aryl–heteroaryl boronate complex, which triggered 1,2-migration from boron to the carbon atom. Subsequent oxidation of the intermediate boronic ester afforded heterobiaryls in good yield. A comprehensive 11B NMR study has been conducted to support the mechanism. The cross coupling between two nucleophilic cross coupling partners without transition metals reveals a reliable manifold to procure heterobiaryls in good yields. Various heterocycles like furan, thiophene, benzofuran, benzothiophene, and indole are well tolerated. Finally, we have successfully demonstrated the gram scale synthesis of the intermediates for an anticancer drug and OLED material using our methodology.
- Paul, Swagata,Das, Kanak Kanti,Manna, Samir,Panda, Santanu
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supporting information
p. 1922 - 1927
(2020/02/04)
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- σ-Bond initiated generation of aryl radicals from aryl diazonium salts
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σ-Bond nucleophiles and molecular oxygen transform aryl diazonium salts into aryl radicals. Experimental and computational studies show that Hantzsch esters transfer hydride to aryl diazonium species, and that oxygen initiates radical fragmentation of the diazene intermediate to produce aryl radicals. The operational simplicity of this addition-fragmentation process for the generation of aryl radicals, by a polar-radical crossover mechanism, has been illustrated in a variety of bond-forming reactions.
- Chan, Bun,McErlean, Christopher S. P.,Nashar, Philippe E.,Tatunashvili, Elene
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p. 1812 - 1819
(2020/03/17)
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- Black phosphorus as a metal-free, visible-light-active heterogeneous photoredox catalyst for the direct C-H arylation of heteroarenes
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Black phosphorus (BP) is for the first time employed as a metal-free, heterogeneous photoredox catalyst for the direct C-H arylation of heteroarenes with aryl diazonium salts. The arylated heteroarenes are obtained in moderate to good yields under visible-light illumination, and the protocol is shown to be applicable for the scale-up synthesis.
- Kalay, Erbay,Kü?ükke?eci, Hüseyin,Kilic, Haydar,Metin, ?nder
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supporting information
p. 5901 - 5904
(2020/06/04)
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- C-H Arylation of Thiophenes with Aryl Bromides by a Parts-per-Million Loading of a Palladium NNC-Pincer Complex
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A palladium NNC-pincer complex efficiently catalyzed the direct arylation of thiophene derivatives with extremely low palladium loadings of the order of parts per million. Thus, the reaction of various thiophenes with aryl bromides in the presence of 25-100 mol ppm of chlorido[(2-phenyl-κ- C 2)-9-phenyl-1,10-phenanthroline-κ 2- N, N ′]palladium(II) NNC-pincer complex, K 2CO 3, and pivalic acid in N, N -dimethyl acetamide afforded the corresponding 2- or 5-arylated thiophenes in good to excellent yields. A combination of the present C-H arylation and Hiyama coupling with the same NNC-pincer complex provides an efficient synthesis of unsymmetrical 2,5-thiophenes with catalyst loadings at mol ppm levels.
- Purta, Anggi Eka,Ichii, Shun,Tazawa, Aya,Uozumi, Yasuhiro
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supporting information
p. 1634 - 1638
(2020/08/28)
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- Immobilized Pd on a NHC functionalized metal–organic framework MIL-101(Cr): an efficient heterogeneous catalyst in Suzuki?Miyaura coupling reaction in water
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A novel Pd?NHC functionalized metal–organic framework (MOF) based on MIL-101(Cr) was synthesized and used as an efficient heterogeneous catalyst in the C-C bond formation reactions. Using this heterogeneous Pd catalyst system, the Suzuki?Miyaura coupling reaction was accomplished well in water, and coupling products were obtained in good to excellent yields in short reaction time. The Pd?NHC?MIL-101(Cr) was characterized using some different techniques, including Fourier transform-infrared, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, inductively coupled plasma and elemental analysis. The microscopic techniques showed the discrete octahedron structure of MIL-101(Cr), which is also stable after chemical modification process to prepare the catalyst system. The TEM images of the catalyst showed the existence of palladium nanoparticles immobilized in the structure of the catalyst, while no reducing agent was used. It seems that the NHC groups and imidazolium moieties in the structure of the MOF can reduce Pd (II) to Pd (0) species. This modified MOF substrate can also prevent aggregation of Pd nanoparticles, resulting in high stability of them in organic transformation. The Pd?NHC?MIL-101(Cr) catalyst system could be simply extracted from the reaction mixture, providing an efficient synthetic method for the synthesis of biaryls derivatives using the aforementioned coupling reaction. The Pd?NHC?MIL-101(Cr) catalyst could be recycled in this organic reaction with almost consistent catalytic efficiency.
- Khalafi-Nezhad, Ali,Niknam, Esmaeil,Panahi, Farhad
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- Taming troublesome suzuki-miyaura reactions in water solution of surfactants by the use of lecithin: A step beyond the micellar model
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The use of water solutions of industrial and designer surfactants enables performing a wide variety of chemical transformations on hydrophobic precursors. Most reactions are clean, fast, and efficient with vast benefits for overall sustainability. The wid
- Ceriani, Chiara,Ghiglietti, Erika,Sassi, Mauro,Mattiello, Sara,Beverina, Luca
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supporting information
p. 2604 - 2610
(2020/12/29)
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- One-step synthesis of magnetically recyclable palladium loaded magnesium ferrite nanoparticles: application in synthesis of anticancer drug PCI-32765
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Novel Palladium nanoparticles supported nano Magnesium ferrite catalyst (Pd/MgFe2O4) was synthesized by one-step ultrasound assisted coprecipitation. In-situ formed by-products assisted salt cage calcination approach was employed to
- Dasari, Gopala Krishna,Sunkara, Satyaveni,Gadupudi, Purna Chandra Rao
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p. 753 - 763
(2020/02/13)
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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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- Stille coupling method for catalyzing aromatic nitro compound by transition metal
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The invention provides a Stille coupling method for catalyzing aromatic nitro compound by transition metal. According to the method, in a nitrogen protection atmosphere, an aromatic nitro compound andan organic tin compound are used as substrates in an organic solvent, a cross coupling reaction is carried out under the action of an alkali under the action of a transition metal catalyst and a ligand, and the aromatic compound is obtained through a column chromatography or recrystallization method. The method is easy to operate, low in price, high in product conversion rate and good in substrate applicability; the method can be used for synthesizing a series of aromatic compounds, and the compounds have wide application values in the fields of pesticides, medicines, materials and the like.
- -
-
Paragraph 0025; 0028; 0052-0054
(2020/08/02)
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- N,S-chelating triazole-thioether ligand for highly efficient palladium-catalyzed Suzuki reaction
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1,2,3-Triazole-thioether compounds could serve as efficient ligands for Pd-catalyzed Suzuki reactions of various aryl iodides, bromides and chlorides. The reactions feature wide substrate scope and mild reaction conditions. Besides, shorter reaction time, lower catalyst loadings and quantitative yields with a turnover-frequency (TOF) value of up to 11,880 h?1 are other advantageous of this attractive protocol. The crystal structure analyses and computational studies revealed that the higher catalytic activity of the corresponding chelated palladium complex ascribed to the lower energy gap and the lower redox potential.
- Yan, Qiong,Zheng, Lei,Li, Miaomiao,Chen, Yunfeng
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p. 101 - 105
(2019/07/19)
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- An efficient Pd(II)-(2-aminonicotinaldehyde) complex as complementary catalyst for the Suzuki-Miyaura coupling in water
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An efficient new Pd(II)-(2-aminonicotinaldehyde)-catalyzed Suzuki-Miyaura coupling of the aryl halides (Br, Cl and I) and organoboronic acids at moderate temperature in water is described. Low catalyst loading, easy accessibility, being an air-stable catalyst, functional group compatibility, and water as the reaction medium are some of the key features of this synthetic method. This protocol is also applicable for gram scale.
- Thunga, Sanjeeva,Poshala, Soumya,Anugu, Naveenkumar,Konakanchi, Ramaiah,Vanaparthi, Satheesh,Kokatla, Hari Prasad
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supporting information
p. 2046 - 2048
(2019/07/04)
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- Metal-Free Aerobic Oxidative Selective C-C Bond Cleavage in Heteroaryl-Containing Primary and Secondary Alcohols
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A transition-metal-free aerobic oxidative selective C-C bond-cleavage reaction in primary and secondary heteroaryl alcohols is reported. This reaction was highly efficient and tolerated various heteroaryl alcohols, generating a carboxylic acid derivative and a neutral heteroaromatic compound. Experimental studies combined with density functional theory calculations revealed the mechanism underlying the selective C-C bond cleavage. This strategy also provides an alternative simple approach to carboxylation reaction.
- Xia, Anjie,Qi, Xueyu,Mao, Xin,Wu, Xiaoai,Yang, Xin,Zhang, Rong,Xiang, Zhiyu,Lian, Zhong,Chen, Yingchun,Yang, Shengyong
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supporting information
(2019/05/07)
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- Synthesis of heterobiaryls via Suzuki-Miyaura coupling reaction of potassium aryltrifluoroborates with heteroaryl halides in aqueous systems
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A variety of heterobiaryl compounds have been synthesized by the Suzuki-Miyaura coupling reactions of heteroaryl halides with potassium aryltrifluoroborates. Pd (OAc)2 was found to be highly efficient for the Suzuki-Miyaura coupling reactions of various heteroaryl halides with potassium aryltrifluoroborates in aqueous systems, delivering the corresponding heterobiaryl compounds in good to excellent yields.
- Liu, Leifang,Zhao, Kai,Li, Wenbo,Liu, Mingli,Chen, Yuting,Dong, Yan
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- Phenalenyl Based Aluminum Compound for Catalytic C-H Arylation of Arene and Heteroarenes at Room Temperature
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Main group metal based catalysis has been considered to be a cost-effective alternative way to the transition metal based catalysis, due to the high abundance of main group metals in the Earth's crust. Among the main group metals, aluminum is the most abundant (7-8%) in the Earth's crust, making the development of aluminum based catalysts very attractive. So far, aluminum based compounds have been popularly used as Lewis acids in a variety of organic reactions, but chemical transformation demanding a redox based process has never utilized an Al(III) complex as a catalyst. Herein, we tuned the redox noninnocence behavior of a phenalenyl ligand by coupling with Al(III) ion, which subsequently can store the electron upon reduction with K to carry out direct C-H arylation of heteroarenes/mesitylene at ambient temperature. A mechanistic investigation revealed that a three-electron reduced phenalenyl based triradical aluminum(III) complex plays the key role in such catalysis. The electronic structure of the catalytically active triradical species has been probed using EPR spectroscopy, magnetic susceptibility measurements, and electronic structure calculations using a DFT method.
- Vardhanapu, Pavan K.,Ahmed, Jasimuddin,Jose, Anex,Shaw, Bikash Kumar,Sen, Tamal K.,Mathews, Amita A.,Mandal, Swadhin K.
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p. 289 - 299
(2019/01/10)
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- Pd-catalyzed C–H bond activation of Indoles for Suzuki reaction
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Abstract: We present a practical method for Suzuki coupling by which unprotected or N-protected indoles may be selectively arylated in the C2-position through direct C–H bond activation by electrophilic Pd(TFA) 2 catalyst. The protocol is operationally simple as it is carried out in dioxane/water mixture, and air as the sole oxidant at room temperature. Various 2-arylated indoles were obtained in good yields. The protocol works for benzofuran, pyrrole and thiophene also. Graphic abstract: Selective C-2 arylation of heterocycles using Pd(II) catalyst via C–H activation was performed under ambient condition. C3–C2 migration of organopalladium intermediate controls the reaction pathway.[Figure not available: see fulltext.].
- Banerjee, Isita,Ghosh, Keshab Ch,Sinha, Surajit
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- Palladium decorated on a new dendritic complex with nitrogen ligation grafted to graphene oxide: Fabrication, characterization, and catalytic application
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Immobilized Pd nanoparticles on a new ligand, namely, tris(pentaethylene-pentamine)triazine supported on graphene oxide (Pdnp-TPEPTA(L)-GO) was introduced as a novel and robust heterogeneous catalyst for use in C-C bond formation reaction. The Pdnp-TPEPTA(L)-GO catalyst was synthesized by complexation of Pd with TPEPTA as a ligand with high N-ligation sites that were supported on graphene oxide through 3-chloropropyltrimethoxysilane. The prepared catalyst was characterized using some microscopic and spectroscopic techniques. The TPEPTA(L)-GO substrate is a 2D heterogeneous catalyst with a high specific surface area and a large amount of N-ligation sites. The Pdnp-TPEPTA(L)-GO catalyst used in the C-C bond formation reaction between aryl or heteroaryl and phenylboronic acid derivatives was applied towards the synthesis of biaryl units in high isolated yields. Notably, a series of competing experiments were performed to establish the selectivity trends of the presented method. Also, this catalyst system was reusable at least six times without a significant decrease in its catalytic activity.
- Golestanzadeh, Mohsen,Naeimi, Hossein
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p. 27560 - 27573
(2019/09/12)
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- Sustainable Ligand-Free, Palladium-Catalyzed Suzuki–Miyaura Reactions in Water: Insights into the Role of Base
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A simple and efficient system was developed for the ligand-free Pd-catalyzed Suzuki–Miyaura reaction in water under mild conditions. Quaternary ammonium hydroxides with long chains were found to be very suitable bases. This ligand-free Pd-catalyzed Suzuki–Miyaura reaction showed improved durability in water with Pd loadings decreased to ppm level. Bases were shown to stabilize active palladium species in addition to acting as a base during the catalytic process. In the catalytic system with a strong base, the soluble active PdII ion exhibited anti-reduction properties, which prevented aggregation and deactivation of Pd species. The entire catalytic system could be recycled after separating the product by simple filtration. The water-compatible and air-stable effective catalytic protocol described herein represents an attractive and green synthetic advance in Suzuki–Miyaura couplings.
- Wang, Yanyan,Liu, Yuanyuan,Zhang, Wei-qiang,Sun, Huaming,Zhang, Kan,Jian, Yajun,Gu, Quan,Zhang, Guofang,Li, Jiyang,Gao, Ziwei
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p. 5265 - 5273
(2019/11/29)
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- Perylenequinonoid-catalyzed photoredox activation for the direct arylation of (het)arenes with sunlight
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Naturally occurring perylenequinonoid pigments (PQPs) have attracted considerable attention owing to their excellent properties of photosensitization. They have been widely investigated as an aspect of photophysics and photobiology. However, their applications in photocatalysis are yet to be explored. We report here that sunlight along with 1 mol% cercosporin, which is one of the perylenequinonoid pigments, catalyzes the direct C-H bond arylation of (het)arenes by a photoredox process with good regioselectivity and broad functional group compatibility. Furthermore, a gram-scale reaction with great conversions of substrates was achieved even by a cercosporin-containing supernatant without organic solvent extraction and purification after liquid fermentation. Thus we set up a bridge between microbial fermentation and organic photocatalysis for chemical reactions in a sustainable, environmentally friendly manner.
- Zhang, Shiwei,Tang, Zhaocheng,Bao, Wenhao,Li, Jia,Guo, Baodang,Huang, Shuping,Zhang, Yan,Rao, Yijian
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supporting information
p. 4364 - 4369
(2019/05/10)
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- Palladium-catalyzed C-H formylation of electron-rich heteroarenes through radical dichloromethylation
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A novel palladium-catalyzed C-H formylation of electron-rich N-, O-, and S-containing heteroarenes has been developed. The key to success is that the commercially available BrCHCl2 was used as a stoichiometric carbonyl source. Mechanistic investigations indicated that different from the known Reimer-Tiemann reaction, this net C-H formylation proceeded through an electrophilc radical-type path.
- Bao, Yan,Wang, Jian-Yong,Zhang, Ya-Xuan,Li, Yan,Wang, Xi-Sheng
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supporting information
p. 3147 - 3150
(2018/07/13)
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- Air-Stable [(R3P)PdCl2]2 Complexes of Neopentylphosphines as Cross-Coupling Precatalysts: Catalytic Application and Mechanism of Catalyst Activation and Deactivation
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Air-stable [(R3P)PdCl2]2 complexes with di-tert-butylneopentylphosphine (DTBNpP, 1a) or trineopentylphosphine (TNpP, 1b) ligands have been applied to Suzuki cross-coupling reactions, and the mechanism of their conversion to the active LPd0 catalyst species has been studied. Precatalysts 1a,b provide effective catalysts for Suzuki cross-coupling of aryl bromides at room temperature, even when the reactions are performed in air. The precatalyst systems provided much higher activity catalysts in toluene/water in comparison to acetonitrile/water. Precatalyst loadings could be decreased by a factor of 50 in toluene in comparison to acetonitrile, while achieving equal or better yields. In acetonitrile/water, ligand metalation to form a [(κ2-P,C-DTBNpP)PdX]2 palladacycle was found to compete with formation of the active Pd(0) species. The palladacycle shows low catalytic activity; thus, its formation represents a catalyst deactivation pathway. In toluene, clean formation of the active Pd(0) species occurs without competitive palladacycle formation. The improved selectivity to form the active Pd(0) species in toluene appears to account for the higher activity of the precatalysts in toluene/water.
- Barnett, Kerry L.,Howard, James R.,Treager, Colin J.,Shipley, Adam T.,Stullich, Renee M.,Qu, Fengrui,Gerlach, Deidra L.,Shaughnessy, Kevin H.
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supporting information
p. 1410 - 1424
(2018/05/23)
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- Base-free nickel-catalysed decarbonylative Suzuki–Miyaura coupling of acid fluorides
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The Suzuki–Miyaura cross-coupling of organoboron nucleophiles with aryl halide electrophiles is one of the most widely used carbon–carbon bond-forming reactions in organic and medicinal chemistry1,2. A key challenge associated with these transformations is that they generally require the addition of an exogenous base, the role of which is to enable transmetallation between the organoboron nucleophile and the metal catalyst3. This requirement limits the substrate scope of the reaction because the added base promotes competitive decomposition of many organoboron substrates3–5. As such, considerable research has focused on strategies for mitigating base-mediated side reactions6–12. Previous efforts have primarily focused either on designing strategically masked organoboron reagents (to slow base-mediated decomposition)6–8 or on developing highly active palladium precatalysts (to accelerate cross-coupling relative to base-mediated decomposition pathways)10–12. An attractive alternative approach involves identifying combinations of catalyst and electrophile that enable Suzuki–Miyaura-type reactions to proceed without an exogenous base12–14. Here we use this approach to develop a nickel-catalysed coupling of aryl boronic acids with acid fluorides15–17, which are formed in situ from readily available carboxylic acids18–22. This combination of catalyst and electrophile enables a mechanistic manifold in which a ‘transmetallation-active’ aryl nickel fluoride intermediate is generated directly in the catalytic cycle13,16. As such, this transformation does not require an exogenous base and is applicable to a wide range of base-sensitive boronic acids and biologically active carboxylic acids.
- Malapit, Christian A.,Bour, James R.,Brigham, Conor E.,Sanford, Melanie S.
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p. 100 - 104
(2018/11/25)
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- An Iron-Based Long-Lived Catalyst for Direct C?H Arylation of Arenes and Heteroarenes
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Direct C?H arylation of arenes and heteroarenes to biaryls at ambient temperature has been accomplished using a phenalenyl-supported iron(III) catalyst. The present catalyst requires a chemical reductant such as potassium and functions without any light stimulation. C?H arylation of various heteroarenes including pyridine as well as unactivated arene such as benzene delivered good to excellent yield (28 examples, up to 92 %) at room temperature. A combined effort based on experiments and theoretical calculations established that a phenalenyl-based radical species (generated by chemical reduction of the iron(III) coordinated phenalenyl complex) plays key role during the catalysis. Furthermore, this catalyst displayed remarkable stability during the catalysis, as evident from the fact that it was still usable over ten consecutive catalytic runs without losing its catalytic efficiency.
- Chakraborty, Soumi,Ahmed, Jasimuddin,Shaw, Bikash Kumar,Jose, Anex,Mandal, Swadhin K.
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p. 17651 - 17655
(2018/11/10)
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- Oxidative Cross-Coupling of Boron and Antimony Nucleophiles via Palladium(I)
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The use of an isolatable, monomeric Pd(I) complex as a catalyst for the oxidative cross-coupling of aryl-antimony and aryl-boron nucleophiles is reported. This reaction tolerates a wide variety of substrates, with >20:1 selectivity for cross-coupled products. This strategy offers a new approach to achieving the selective cross-coupling of nucleophiles.
- Simpson, Quillon,Sinclair, Matthew J. G.,Lupton, David W.,Chaplin, Adrian B.,Hooper, Joel F.
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supporting information
p. 5537 - 5540
(2018/09/21)
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- A Highly Active Cobalt Catalyst System for Kumada Biaryl Cross-Coupling
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A highly active cobalt catalyst system has been developed for the cross-coupling reactions of arylmagnesium reagents and aryl bromides. In the presence of 1 mol% CoCl 2, 2 mol% IPr·HCl and 2 mol% NaO t Bu, a wide range of (hetero)biaryls are prepared in 51-99% yields at room temperature within a short reaction time.
- Wu, Wenqin,Duong, Hung A.
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supporting information
p. 1199 - 1202
(2018/03/23)
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- Regioselective Halogenation of Arenes and Heterocycles in Hexafluoroisopropanol
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Regioselective halogenation of arenes and heterocycles with N-halosuccinimides in fluorinated alcohols is disclosed. Under mild condition reactions, a wide diversity of halogenated arenes are obtained in good yields with high regioselectivity. Additionally, the versatility of the method is demonstrated by the development of one-pot sequential halogenation and halogenation-Suzuki cross-coupling reactions.
- Tang, Ren-Jin,Milcent, Thierry,Crousse, Benoit
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p. 930 - 938
(2018/01/28)
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- N-heterocyclic carbene-Pd(II) complex based on theophylline supported on Fe3O4@SiO2 nanoparticles: Highly active, durable and magnetically separable catalyst for green Suzuki-Miyaura and Sonogashira-Hagihara coupling reactions
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In this paper, a novel heterogeneous palladium catalyst was synthesized by anchoring N-heterocyclic carbene-Pd(II) complex based on theophylline on magnetic Fe3O4@SiO2 nanoparticles. The synthesized magnetic composite was characterized by fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA), vibration sample magnetometry (VSM), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), N2 adsorption-desorption isotherm analysis (BET), UV–vis spectroscopy and elemental analysis. Also, loading content of palladium on the catalyst was measured by inductive coupled plasma (ICP) analysis. The synthesized catalyst was used successfully for the Suzuki cross-coupling reactions of various aryl halides (I, Br, Cl) with phenylboronic acids. This reaction was best performed in water as a green solvent in the presence of just 0.37–0.5 mol% of the catalyst at 60 °C. Also, we have reported this recyclable catalytic system as a stable phosphine-free Pd catalyst for the Sonogashira cross-coupling of aryl halides (I, Br, Cl) with terminal aromatic and aliphatic alkynes under solvent-free conditions. All coupling reactions proceeded with good to excellent yields. The catalyst showed good stability and was recovered and reused for eight reaction cycles without a significant loss in its catalytic activity. Also, the leaching of the catalyst has been examined by a hot filtration test and ICP-AES analysis.
- Esmaeilpour, Mohsen,Sardarian, Ali Reza,Firouzabadi, Habib
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- Non-Directed Cross-Dehydrogenative (Hetero)arylation of Allylic C(sp3)?H bonds enabled by C?H Activation
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Herein, we report the selective, non-directed and cross-dehydrogenative coupling of allylic C(sp3)?H bonds with C(sp2)?H bonds of (hetero)arenes. The methodology employs olefins and (hetero)arenes which are abundantly available chemical feedstocks, and could be applied in late-stage functionalization reactions of pharmaceuticals. Furthermore, the system exclusively delivers the allylic C?C coupling products highlighting the preservation of the olefin substitution pattern for further derivatization.
- Lerchen, Andreas,Knecht, Tobias,Koy, Maximilian,Ernst, Johannes B.,Bergander, Klaus,Daniliuc, Constantin G.,Glorius, Frank
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supporting information
p. 15248 - 15252
(2018/10/20)
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- Palladium nanoparticles immobilized on EDTA-modified Fe3O4@SiO2 nanospheres as an efficient and magnetically separable catalyst for Suzuki and Sonogashira cross-coupling reactions
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In this study, a novel heterogeneous palladium catalyst was synthesized by anchoring palladium onto ethylenediaminetetraacetic acid (EDTA)-coated Fe3O4@SiO2 magnetic nanocomposite and used for the Suzuki and Sonogashira cross-coupling reactions. The properties of the magnetic catalyst were characterized by FT-IR, XRD, TEM, FE-SEM, DLS EDX, XPS, N2 adsorption-desorption isotherm analysis, TGA, VSM, elemental analysis and the loading level of Pd in catalyst was measured to be 0.51?mmol/g by ICP. The catalyst was used in Suzuki cross-coupling reactions of various aryl halides, including less reactive chlorobenzenes with phenylboronic acid without any additive or ligand under green conditions. Furthermore, we have reported this recyclable catalytic system for Sonogashira cross-coupling reactions of various aryl halides (I, Br, Cl) under copper and ligand-free conditions in the presence of DMF/H2O (1:2/v:v) as a solvent. The magnetic catalyst could also be separated by an external magnet and reused six times without any significant loss of activity.
- Esmaeilpour, Mohsen,Zahmatkesh, Saeed,Fahimi, Nafiseh,Nosratabadi, Mehran
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- Recyclable Pd/CuFe2O4 nanowires: A highly active catalyst for C-C couplings and synthesis of benzofuran derivatives
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Pd/CuFe2O4 nanowire-catalyzed cross coupling transformations are described. Notably, these reactions showed excellent functional group tolerance. Further, the protocol is applied to a one-pot synthesis of benzofurans via a Sonogashira coupling and intramolecular etherification sequence. The catalyst was reused and found to maintain its activity and stability.
- Lakshminarayana, Bhairi,Chakraborty, Jhonti,Satyanarayana,Subrahmanyam, Ch.
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p. 21030 - 21039
(2018/06/13)
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- Continuous Visible-Light Photoflow Approach for a Manganese-Catalyzed (Het)Arene C?H Arylation
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Manganese photocatalysts enabled versatile room-temperature C?H arylation reactions by means of continuous visible-light photoflow, thus allowing for efficient C?H arylations in 30 minutes with ample scope. The robustness of the manganese-catalyzed photoflow strategy was shown by visible light-induced gram-scale synthesis, clearly outperforming the batch performance.
- Liang, Yu-Feng,Steinbock, Ralf,Yang, Long,Ackermann, Lutz
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supporting information
p. 10625 - 10629
(2018/08/01)
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- Synthesis method and application of terephthalyl alcohol-derived bidentate phosphite ligand
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The invention discloses a synthesis method and an application of a terephthalyl alcohol-derived bidentate phosphite ligand. The ligand has the following structural formula defined in the specification, wherein R is H or t-Bu. The ligand is a white solid, and is stable in structure, simple in synthesis, high in yield and easy to prepare in large quantities; in a nitrogen atmosphere, the ligand anda palladium salt are subjected to reaction in an organic solvent to obtain a ligand/palladium catalyst, a Suzuki-Miyaura reaction is catalyzed, the reaction conversion rate is high and the substrate universality is high.
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Paragraph 0033; 0036; 0037; 0050
(2019/01/06)
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- Photo-oxidative Cross-Dehydrogenative Coupling-Type Reaction of Thiophenes with α-Position of Carbonyls Using a Catalytic Amount of Molecular Iodine
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A metal-free photo-oxidative intermolecular C-H/C-H coupling reaction of thiophenes is demonstrated with carbonyls using a catalytic amount of molecular iodine. In this system, molecular oxygen in the air acted as a terminal oxidant to regenerate molecular iodine. A mechanistic study was also performed.
- Sudo, Yusuke,Yamaguchi, Eiji,Itoh, Akichika
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supporting information
p. 1610 - 1613
(2017/04/13)
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- Ecocatalyzed Suzuki cross coupling of heteroaryl compounds
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A bio-based EcoPd was developed for the Suzuki cross coupling of heteroaryl compounds. Based on the ability of Eichhornia crassipes to bioconcentrate Pd in its roots, we addressed the transformation of plant-derived Pd metals to green catalysts. The methodology is based on eco-friendly procedures. It allowed the preparation of a wide range of heterocyclic biaryl and heterocyclic-heterocyclic biaryl compounds, with a low Pd catalyst loading. EcoPd was found to have the ideal microstructure to promote complex Suzuki reactions without ligands or additives. For the first time, post-reaction solution was treated by rhizofiltration. The resulting EcoPd has been reused with the same performance. This work has established the ecocatalysis concept as a powerful strategy for Pd sustainability, with the development of homogeneous catalysts that are easily recycled and reused.
- Clavé, Guillaume,Pelissier, Franck,Campidelli, Stéphane,Grison, Claude
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p. 4093 - 4103
(2017/09/07)
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- Gram-scale synthesis of aligned C3N4-polypyrrole heterojunction aerogels with tunable band structures as efficient visible and near infrared light-driven metal-free photocatalysts
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The assembly of aligned porous materials from simple building blocks is of widespread interest for engineering materials with enhanced and synergistic properties. To date, however, how to develop 3D heterojunction aerogels with aligned porosity based on 2D semiconductor materials and 1D conducting polymers for solar energy conversion in the visible and near-infrared (NIR) light region remains a significant challenge. Here a new class of gram-scale 3D aligned heterojunction aerogels of polypyrrole (PPy)/C3N4 nanosheets (NSs) were designed and synthesized by directional freezing of polypyrrole (PPy)/polyvinyl alcohol (PVA) and C3N4 NS aqueous suspension. The synthesis of aligned C3N4-PPy heterojunction aerogels can be achieved on a large scale. The formed aerogel expresses stable and uniform dispersion of the two building blocks, long-range channel aligned structures along the whole monolithic sample, and additional special complementary optical properties between PPy and C3N4 NSs. Based on the above unique structure and optical properties, this novel metal-free heterojunction aerogel exhibits excellent photocatalytic activity and long-term stability for direct arylation of heteroaromatics under visible and near infrared (NIR) light irradiation at room temperature, far exceeding those of the single- and two-component systems. Our work therefore not only provides a new approach to obtain aligned heterojunction aerogels based on metal free semiconductors but also paves a way to develop gram-scale aerogels as a new type of highly efficient visible and NIR light induced heterogeneous photocatalyst.
- Liu, Jian,Wang, Hao,Bai, Jinwei,Li, Tianrong,Yang, Yanmei,Peng, Yong,Wang, Baodui
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p. 24920 - 24928
(2017/12/15)
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- Nickel-Catalyzed Cross-Coupling Reaction of Aryl Sulfoxides with Arylzinc Reagents: When the Leaving Group is an Oxidant
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Nickel-catalyzed Negishi-type cross-coupling of aryl methyl sulfoxides with arylzinc reagents has been developed. By consuming the catalyst-oxidizing methanesulfenate anion through oxidative homocoupling of the arylzinc reagent, smooth catalyst turnover c
- Yamamoto, Keita,Otsuka, Shinya,Nogi, Keisuke,Yorimitsu, Hideki
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p. 7623 - 7628
(2017/11/14)
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- Design, Synthesis, and Application of Polymer-Supported Silicon-Transfer Agents for Cross-Coupling Reactions with Organolithium Reagents
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The initial design, synthesis, and validation of polymer-supported siloxane transfer agents have been achieved that permit the direct use of organolithium reagents in the palladium-catalyzed cross-coupling reactions. Through rational design, two generations of polymer support were developed that significantly simplify product purification and the transfer agent recycling.
- Nguyen, Minh H.,O'Brien, Kevin T.,Smith, Amos B.
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p. 11056 - 11071
(2017/10/27)
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- Method for cleaving alpha carbon-carbon single bonds in ketone under condition of metal-free catalysis
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The invention discloses a method for selectively activating and cleaving alpha carbon-carbon single bonds in ketone under the condition of metal-free catalysis. The method is characterized in that the alpha carbon-carbon single bonds in the ketone are activated and cleaved by solvent induction and driving of intermediate structure factors formed by the ketone and hydrazine without metal catalysts. Transition metal for catalysis is omitted, the method is environmentally friendly, reaction cost is reduced to a certain degree, methodology of selective cleavage of the carbon-carbon single bonds is enriched, and a new idea is provided for activation of inertial chemical bonds under mild conditions.
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Paragraph 0017; 0028
(2017/10/07)
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- Manganese-Catalyzed Aerobic Heterocoupling of Aryl Grignard Reagents
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An improved protocol has been developed for the MnCl2-catalyzed cross-coupling reaction of two arylmagnesium bromides under dioxygen. The reaction was achieved by using the Grignard reagents in a 2:1 ratio and 20 % of MnCl2. Very good yields of the heterocoupling product were obtained when the limiting Grignard reagent underwent little homocoupling under the reaction conditions. Arylmagnesium bromides that contain p-methoxy, p-(dimethylamino), p-fluoro, and p-chloro substituents were shown to afford high product yields in the cross-coupling reactions with a variety of substituted aryl Grignard reagents. Heterocyclic Grignard reagents, on the other hand, were less effective substrates for this transformation because of the rapid homocoupling of these reagents under the reaction conditions.
- Ghaleshahi, Hajar Golshahi,Antonacci, Giuseppe,Madsen, Robert
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p. 1331 - 1336
(2017/03/23)
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