- Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions
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The combination of supported ionic liquids and immobilized NHC–Pd–RuPhos led to active and more stable systems for the Negishi reaction under continuous flow conditions than those solely based on NHC–Pd–RuPhos. The fine tuning of the NHC–Pd catalyst and the SILLPs is a key factor for the optimization of the release and catch mechanism leading to a catalytic system easily recoverable and reusable for a large number of catalytic cycles enhancing the long-term catalytic performance.
- Alcázar, Jesús,García-Verdugo, Eduardo,Luis, Santiago V.,Macia, María,Peris, Edgar,Porcar, Raúl
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Read Online
- Aromatization as an Impetus to Harness Ketones for Metallaphotoredox-Catalyzed Benzoylation/Benzylation of (Hetero)arenes
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Herein we report ketones as feedstock materials in radical cross-coupling reactions under Ni/photoredox dual catalysis. In this approach, simple condensation first converts ketones into prearomatic intermediates that then act as activated radical sources for cross-coupling with aryl halides. Our strategy enables the direct benzylation/benzoylation of (hetero)arenes under mild reaction conditions with high functional group tolerance.
- Lee, Shao-Chi,Li, Li-Yun,Tsai, Zong-Nan,Lee, Yi-Hsin,Tsao, Yong-Ting,Huang, Pin-Gong,Cheng, Cheng-Ku,Lin, Heng-Bo,Chen, Ting-Wei,Yang, Chung-Hsin,Chiu, Cheng-Chau,Liao, Hsuan-Hung
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- Nickel-Catalyzed Reductive Cross-Coupling of Benzylic Sulfonium Salts with Aryl Iodides
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A nickel-catalyzed cross-electrophile coupling of benzylic sulfonium salts with aryl iodides has been developed, providing direct access to diarylalkanes from readily available and stable coupling partners. Preliminary mechanistic studies suggest that the C-S bond cleavage proceeds through a single-electron transfer process to generate a benzylic radical.
- Wang, Wei,Wu, Fan,Yao, Ken
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p. 361 - 366
(2022/03/07)
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- Desulfurative Ni-Catalyzed Reductive Cross-Coupling of Benzyl Mercaptans/Mercaptoacetates with Aryl Halides
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The C-S activation and sulfur removal from native thiols is challenging, which limits their application as feedstock materials in organic synthesis despite their natural abundance. Herein, we introduce a per-/polyfluoroaryl moiety, which serves as a redox-active scaffold, into sp3-hybridized thiols to activate the C-S bond. Using a Ni catalyst with MgBr2 as an additive, the S group can be removed to yield an aliphatic radical that can react with an aryl halide in a reductive cross-coupling.
- Chan, Cheng-Lin,Hsu, Che-Ming,Lee, Shao-Chi,Li, Li-Yun,Liao, Hsuan-Hung,Mi?oza, Shinje,Tsai, Hao-En,Tsai, Zong-Nan,Tsao, Yong-Ting
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- Electrochemically Enabled, Nickel-Catalyzed Dehydroxylative Cross-Coupling of Alcohols with Aryl Halides
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As alcohols are ubiquitous throughout chemical science, this functional group represents a highly attractive starting material for forging new C-C bonds. Here, we demonstrate that the combination of anodic preparation of the alkoxy triphenylphosphonium ion and nickel-catalyzed cathodic reductive cross-coupling provides an efficient method to construct C(sp2)-C(sp3) bonds, in which free alcohols and aryl bromides - both readily available chemicals - can be directly used as coupling partners. This nickel-catalyzed paired electrolysis reaction features a broad substrate scope bearing a wide gamut of functionalities, which was illustrated by the late-stage arylation of several structurally complex natural products and pharmaceuticals.
- Li, Zijian,Sun, Wenxuan,Wang, Xianxu,Li, Luyang,Zhang, Yong,Li, Chao
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supporting information
p. 3536 - 3543
(2021/03/08)
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- Nickel-Catalyzed Electrochemical C(sp3)?C(sp2) Cross-Coupling Reactions of Benzyl Trifluoroborate and Organic Halides**
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Reported here is the redox neutral electrochemical C(sp2)?C(sp3) cross-coupling reaction of bench-stable aryl halides or β-bromostyrene (electrophiles) and benzylic trifluoroborates (nucleophiles) using nonprecious, bench-stable NiCl2?glyme/polypyridine catalysts in an undivided cell configuration under ambient conditions. The broad reaction scope and good yields of the Ni-catalyzed electrochemical coupling reactions were confirmed by 50 examples of aryl/β-styrenyl chloride/bromide and benzylic trifluoroborates. Potential applications were demonstrated by electrosynthesis and late-stage functionalization of pharmaceuticals and natural amino acid modification, and three reactions were run on gram-scale in a flow-cell electrolyzer. The electrochemical C?C cross-coupling reactions proceed through an unconventional radical transmetalation mechanism. This method is highly productive and expected to find wide-spread applications in organic synthesis.
- Luo, Jian,Hu, Bo,Wu, Wenda,Hu, Maowei,Liu, T. Leo
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p. 6107 - 6116
(2021/02/01)
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- Dynamic Kinetic Cross-Electrophile Arylation of Benzyl Alcohols by Nickel Catalysis
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Catalytic transformation of alcohols via metal-catalyzed cross-coupling reactions is very important, but it typically relies on a multistep procedure. We here report a dynamic kinetic cross-coupling approach for the direct functionalization of alcohols. The feasibility of this strategy is demonstrated by a nickel-catalyzed cross-electrophile arylation reaction of benzyl alcohols with (hetero)aryl electrophiles. The reaction proceeds with a broad substrate scope of both coupling partners. The electron-rich, electron-poor, and ortho-/meta-/para-substituted (hetero)aryl electrophiles (e.g., Ar-OTf, Ar-I, Ar-Br, and inert Ar-Cl) all coupled well. Most of the functionalities, including aldehyde, ketone, amide, ester, nitrile, sulfone, furan, thiophene, benzothiophene, pyridine, quinolone, Ar-SiMe3, Ar-Bpin, and Ar-SnBu3, were tolerated. The dynamic nature of this method enables the direct arylation of benzylic alcohol in the presence of various nucleophilic groups, including nonactivated primary/secondary/tertiary alcohols, phenols, and free indoles. It thus offers a robust alternative to existing methods for the precise construction of diarylmethanes. The synthetic utility of the method was demonstrated by a concise synthesis of biologically active molecules and by its application to peptide modification and conjugation. Preliminary mechanistic studies revealed that the reaction of in situ formed benzyl oxalates with nickel, possibly via a radical process, is an initial step in the reaction with aryl electrophiles.
- Guo, Peng,Wang, Ke,Jin, Wen-Jie,Xie, Hao,Qi, Liangliang,Liu, Xue-Yuan,Shu, Xing-Zhong
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supporting information
p. 513 - 523
(2021/01/12)
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- Visible Light-Catalyzed Benzylic C-H Bond Chlorination by a Combination of Organic Dye (Acr+-Mes) and N-Chlorosuccinimide
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By combining "N-chlorosuccinimide (NCS)"as the safe chlorine source with "Acr+-Mes"as the photocatalyst, we successfully achieved benzylic C-H bond chlorination under visible light irradiation. Furthermore, benzylic chlorides could be converted to benzylic ethers smoothly in a one-pot manner by adding sodium methoxide. This mild and scalable chlorination method worked effectively for diverse toluene derivatives, especially for electron-deficient substrates. Careful mechanistic studies supported that NCS provided a hydrogen abstractor "N-centered succinimidyl radical,"which was responsible for the cleavage of the benzylic C-H bond, relying on the reducing ability of Acr?-Mes.
- Xiang, Ming,Zhou, Chao,Yang, Xiu-Long,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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p. 9080 - 9087
(2020/08/14)
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- Upscaling Photoredox Cross-Coupling Reactions in Batch Using Immersion-Well Reactors
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Herein we describe a straightforward approach for the scale-up of photoredox cross-coupling reactions from milligram to multigram scale using immersion-well batch reactors with minimal reoptimization of the reaction conditions. This approach can be applied to both homogeneous and, more significantly, heterogeneous reaction mixtures. Furthermore, we have used an immersion-well side-loop reactor to perform a reaction on a 400 mmol scale (86 g of aryl bromide).
- Candish, Lisa,Collins, Karl D.,Grimm, Isabelle,Hauer, Simone T.,Lovis, Kai,Schulte, Tim,Wycich, Gina
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supporting information
p. 1185 - 1193
(2020/07/08)
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- PHOTOCATALYST SYSTEM AND USE THEREOF IN A PHOTOCATALYTIC PROCESS
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Photocatalyst system and use thereof in a photochemical process The invention relates to a photocatalyst system comprising, in the absence of a further photosensitizer other than the compound of formula (III) or a mixture thereof: (i) a nickel(II) salt, (
- -
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Page/Page column 33; 35; 37
(2019/06/13)
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- Phosphonic acid mediated practical dehalogenation and benzylation with benzyl halides
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For the first time, by using H3PO3/I2 system, various benzyl chlorides, bromides and iodides were dehalogenated successfully. In the presence of H3PO3, benzyl halides underwent electrophilic substitution reactions with electron-rich arenes, leading to a broad range of diarylmethanes in good yields. These transformations feature green, cheap reducing reagents and metal-free conditions. A possible mechanism was proposed.
- Gao, Jing,Han, Li-Biao,Ma, Yonghao,Tang, Zilong,Wu, Xiaofang,Xiao, Jing
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p. 22343 - 22347
(2019/07/31)
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- Palladium-Catalyzed Hiyama Coupling of Benzylic Ammonium Salts via C-N Bond Cleavage
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The first palladium-catalyzed Hiyama cross-coupling of arylsilanes with benzyltrimethylammonium salts is reported. The reaction proceeds smoothly to facilitate C(sp2)-C(sp3) bond formation via cleavage of the C-N bond and provides a useful approach to various diarylmethanes with a broad substrate scope and excellent functional group tolerance in good to excellent yields.
- Han, Chunyu,Zhang, Zhenming,Xu, Silin,Wang, Kai,Chen, Kaiting,Zhao, Junfeng
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p. 16308 - 16313
(2019/12/25)
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- Deoxygenative cross-electrophile coupling of benzyl chloroformates with aryl iodides
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This work describes Ni-catalyzed cross-electrophile coupling of benzyl chloroformate derivatives with aryl iodides that generates a wide range of diaryl methane products. The mild reaction conditions merit the C-O bond radical fragmentation of benzyl chloroformates via halide abstraction or a single electron reduction by a Ni catalyst. This work offers a new substrate type for cross-electrophile couplings.
- Pan, Yingying,Gong, Yuxin,Song, Yanhong,Tong, Weiqi,Gong, Hegui
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supporting information
p. 4230 - 4233
(2019/05/06)
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- The Dual Role of Benzophenone in Visible-Light/Nickel Photoredox-Catalyzed C?H Arylations: Hydrogen-Atom Transfer and Energy Transfer
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A dual catalytic protocol for the direct arylation of non-activated C(sp3)?H bonds has been developed. Upon photochemical excitation, the excited triplet state of a diaryl ketone photosensitizer abstracts a hydrogen atom from an aliphatic C?H bond. This inherent reactivity was exploited for the generation of benzylic radicals which subsequently enter a nickel catalytic cycle, accomplishing the benzylic arylation.
- Dewanji, Abhishek,Krach, Patricia E.,Rueping, Magnus
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supporting information
p. 3566 - 3570
(2019/02/26)
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- Sp3 C-H Arylation and Alkylation Enabled by the Synergy of Triplet Excited Ketones and Nickel Catalysts
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Triplet ketone sensitizers are of central importance within the realm of photochemical transformations. Although the radical-type character of triplet excited states of diaryl ketones suggests the viability for triggering hydrogen-atom transfer (HAT) and single-electron transfer (SET) processes, among others, their use as multifaceted catalysts in C-C bond-formation via sp3 C-H functionalization of alkane feedstocks still remains rather unexplored. Herein, we unlock a modular photochemical platform for forging C(sp3)-C(sp2) and C(sp3)-C(sp3) linkages from abundant alkane sp3 C-H bonds as functional handles using the synergy between nickel catalysts and simple, cheap and modular diaryl ketones. This method is distinguished by its wide scope that is obtained from cheap catalysts and starting precursors, thus complementing existing inner-sphere C-H functionalization protocols or recent photoredox scenarios based on iridium polypyridyl complexes. Additionally, such a platform provides a new strategy for streamlining the synthesis of complex molecules with high levels of predictable site-selectivity and preparative utility. Mechanistic experiments suggest that sp3 C-H abstraction occurs via HAT from the ketone triplet excited state. We believe this study will contribute to a more systematic utilization of triplet excited ketones as catalysts in metallaphotoredox scenarios.
- Shen, Yangyang,Gu, Yiting,Martin, Ruben
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supporting information
p. 12200 - 12209
(2018/09/27)
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- Nickel-Catalyzed Cross-Electrophile Coupling between Benzyl Alcohols and Aryl Halides Assisted by Titanium Co-reductant
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A nickel-catalyzed cross-electrophile coupling reaction between benzyl alcohols and aryl halides has been developed using a homolytic C-O bond cleavage protocol that has recently been established. The treatment of a benzyl alcohol and aryl halide with a nickel catalyst and low-valent titanium reagent generated from TiCl4(lutidine) (lutidine = 2,6-lutidine) and manganese powder afforded the cross-coupled product in high yield. A mechanistic study indicated the intermediacy of the benzyl radicals that originate from the benzyl alcohols.
- Suga, Takuya,Ukaji, Yutaka
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supporting information
p. 7846 - 7850
(2019/01/14)
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- An Efficient Ga(OTf)3/Isopropanol Catalytic System for Direct Reduction of Benzylic Alcohols
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This study aims to report the first gallium-catalyzed direct reduction of benzylic alcohols using isopropanol as a reductant. The reaction proceeds via gallium catalyst-assisted hydride transfer of the in situ-generated benzylic isopropyl ether. The method generates only water and acetone as byproducts and thus provides an atom-economic and environmentally friendly approach to the synthesis of di- and triarylmethanes, which are important substructures in various bioactive compounds and functional materials. (Figure presented.).
- Sai, Masahiro
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p. 4330 - 4335
(2018/10/15)
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- Phosphite-catalyzed alkoxycarbonylation of aryl diazonium salts
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In this communication, an interesting phosphite-catalyzed alkoxycarbonylation of aryl diazonium salts has been reported. At room temperature and under CO pressure, moderate to good yields of the desired esters can be produced in the absence of bases or an
- Xu, Jian-Xing,Franke, Robert,Wu, Xiao-Feng
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supporting information
p. 6180 - 6182
(2018/09/10)
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- Visible-Light-Induced Nickel-Catalyzed Negishi Cross-Couplings by Exogenous-Photosensitizer-Free Photocatalysis
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The merging of photoredox and transition-metal catalysis has become one of the most attractive approaches for carbon–carbon bond formation. Such reactions require the use of two organo-transition-metal species, one of which acts as a photosensitizer and t
- Abdiaj, Irini,Fontana, Alberto,Gomez, M. Victoria,de la Hoz, Antonio,Alcázar, Jesús
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p. 8473 - 8477
(2018/04/30)
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- Cross-Coupling of Phenol Derivatives with Umpolung Aldehydes Catalyzed by Nickel
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A nickel-catalyzed cross-coupling to construct the C(sp2)-C(sp3) bond was developed from two sustainable biomass-based feedstocks: phenol derivatives with umpolung aldehydes. This strategy features the in situ generation of moisture/air-stable hydrazones from naturally abundant aldehydes, which act as alkyl nucleophiles under catalysis to couple with readily available phenol derivatives. The avoidance of using both halides as the electrophiles and organometallic or organoboron reagents (also derived from halides) as the nucleophiles makes this method more sustainable. Water tolerance, great functional group (ketone, ester, free amine, amide, etc.) compatibility, and late-stage elaboration of complex biological molecules exemplified its practicability and unique chemoselectivity over organometallic reagents.
- Lv, Leiyang,Zhu, Dianhu,Tang, Jianting,Qiu, Zihang,Li, Chen-Chen,Gao, Jian,Li, Chao-Jun
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p. 4622 - 4627
(2018/05/22)
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- Synthetic method of diarylmethanes
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The invention discloses a synthetic method of diarylmethanes. The method is characterized in that benzyl pseudohalide and aromatic boric acid are reacted in an organic solvent under alkaline condition. The method employs easily available raw materials, conversion is realized under effect of no transition metal catalysis, water-free and oxygen-free are not required, Lewis acid catalysis is not required, the method has wide substrate universality, and various substituted diarylmethanes can be synthesized by the method.
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Paragraph 0153; 0154; 0155; 0156; 0157
(2017/08/28)
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- Synthesis of Di- and Triarylmethanes through Palladium-Catalyzed Reductive Coupling of N -Tosylhydrazones and Aryl Bromides
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A palladium-catalyzed reductive coupling between N-tosylhydrazones and aryl bromides has been developed. The reaction provides an efficient method for the synthesis of diarylmethanes and triarylmethanes via the formation of C(sp2)-C(sp3) single bonds. This new methodology for the synthesis of diarylmethanes and triarylmethanes is featured by the ready availability of the starting materials, mild reaction conditions, and the tolerance of wide range of functional groups. The reaction follows a pathway including palladium carbene formation, migratory insertion, and reduction of the alkylpalladium(II) intermediate.
- Xia, Yamu,Hu, Fangdong,Xia, Ying,Liu, Zhenxing,Ye, Fei,Zhang, Yan,Wang, Jianbo
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p. 1073 - 1086
(2017/02/24)
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- Synthesis of Benzyltributylstannanes by the Reaction of N-Tosylhydrazones with Bu3SnH
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An efficient stannylation process with N-tosylhydrazones or directly with carbonyl compounds has been developed. A series of functionalized benzyl- and alkyltributylstannanes can be synthesized in moderate to good yields under transition-metal-free conditions. Tandem transformations involving stannylation/Stille cross-coupling reaction have been carried out without purification of the benzyltributylstannane intermediates to afford a series of diarylmethane derivatives.
- Qiu, Di,Wang, Shuai,Meng, He,Tang, Shengbo,Zhang, Yan,Wang, Jianbo
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p. 624 - 632
(2017/04/26)
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- A Zinc Catalyzed C(sp3)?C(sp2) Suzuki–Miyaura Cross-Coupling Reaction Mediated by Aryl-Zincates
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The Suzuki–Miyaura (SM) reaction is one of the most important methods for C?C bond formation in chemical synthesis. In this communication, we show for the first time that the low toxicity, inexpensive element zinc is able to catalyze SM reactions. The cross-coupling of benzyl bromides with aryl borates is catalyzed by ZnBr2, in a process that is free from added ligand, and is compatible with a range of functionalized benzyl bromides and arylboronic acid pinacol esters. Initial mechanistic investigations indicate that the selective in situ formation of triaryl zincates is crucial to promote selective cross-coupling reactivity, which is facilitated by employing an arylborate of optimal nucleophilicity.
- Procter, Richard J.,Dunsford, Jay J.,Rushworth, Philip J.,Hulcoop, David G.,Layfield, Richard A.,Ingleson, Michael J.
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supporting information
p. 15889 - 15893
(2017/10/24)
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- Coupling of arylboronic acids with benzyl halides or mesylates without adding transition metal catalysts
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We report herein a transition-metal-free coupling reaction of arylboronic acids with benzyl halides and mesylates for the construction of C(sp2)[sbnd]C(sp3) bonds. A unique feature of this coupling reaction is the formation regioisomers in some cases. Mechanistic studies suggest that this reaction may proceed via an unprecedented Friedel–Crafts-type reaction pathway under base conditions with the assistance of boronic acid moiety.
- Wu, Guojiao,Xu, Shuai,Deng, Yifan,Wu, Chaoqiang,Zhao, Xia,Ji, Wenzhi,Zhang, Yan,Wang, Jianbo
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p. 8022 - 8030
(2016/11/19)
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- Donor-Acceptor Fluorophores for Visible-Light-Promoted Organic Synthesis: Photoredox/Ni Dual Catalytic C(sp3)-C(sp2) Cross-Coupling
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We describe carbazolyl dicyanobenzene (CDCB)-based donor-acceptor (D-A) fluorophores as a class of cheap, easily accessible, and efficient metal-free photoredox catalysts for organic synthesis. By changing the number and position of carbazolyl and cyano groups on the center benzene ring, CDCBs with a wide range of photoredox potentials are obtained to effectively drive the energetically demanding C(sp3)-C(sp2) cross-coupling of carboxylic acids and alkyltrifluoroborates with aryl halides via a photoredox/Ni dual catalysis mechanism. This work validates the utility of D-A fluorophores in guiding the rational design of metal-free photoredox catalysts for visible-light-promoted organic synthesis.
- Luo, Jian,Zhang, Jian
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p. 873 - 877
(2016/02/18)
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- Alcohols as Latent Coupling Fragments for Metallaphotoredox Catalysis: Sp3-sp2 Cross-Coupling of Oxalates with Aryl Halides
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Alkyl oxalates, prepared from their corresponding alcohols, are engaged for the first time as carbon radical fragments in metallaphotoredox catalysis. In this report, we demonstrate that alcohols, native organic functional groups, can be readily activated with simple oxalyl chloride to become radical precursors in a net redox-neutral Csp3-Csp2 cross-coupling with a broad range of aryl halides. This alcohol-activation coupling is successfully applied to the functionalization of a naturally occurring steroid and the expedient synthesis of a medicinally relevant drug lead.
- Zhang, Xiaheng,MacMillan, David W.C.
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p. 13862 - 13865
(2016/11/06)
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- Efficient synthesis of diarylmethane derivatives by PdCl2 catalyzed cross-coupling reactions of benzyl chlorides with aryl boronic acids in aqueous medium
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The research provides a simple and efficient method for preparing diarylmethane derivatives using the cross-coupling reaction of benzyl chlorides and aryl boronic acids catalyzed by palladium chloride in DMF aqueous solution without additional ligand.
- Zhao, Guangkuan,Zhang, Kena,Wang, Liang,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
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supporting information
p. 6700 - 6703
(2016/02/03)
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- AsCat and FurCat: New Pd catalysts for selective roomerature Stille cross-couplings of benzyl chlorides with organostannanes
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Two novel succinimide-based palladium complexes, AsCat and FurCat, are highly efficient catalysts for roomerature Stille cross-coupling of organostannanes with benzyl chlorides. The air- and moisture-stable catalysts are prepared in one step, and the coupling reactions proceed with a high selectivity for the benzyl position under mild conditions without the need for additives. This journal is
- Ronson, Thomas O.,Carney, Jonathan R.,Whitwood, Adrian C.,Taylor, Richard J. K.,Fairlamb, Ian J. S.
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supporting information
p. 3466 - 3469
(2015/03/04)
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- Alkylations of Arylboronic Acids including Difluoroethylation/Trifluoroethylation via Nickel-Catalyzed Suzuki Cross-Coupling Reaction
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An efficient alkylation method of functionalized alkyl halides under mild nickel-catalyzed C(sp3)-(sp2) Suzuki cross-coupling conditions is described. The features of this approach are excellent functional group compatibility, low cost nickel catalyst, and the use of a mild base. This is also the first successful example of the nickel-catalyzed direct 2,2-difluoroethylation or 2,2,2-trifluoroethylation of aryl-/heteroarylboronic acids.
- Zhang, Xiaofei,Yang, Chunhao
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supporting information
p. 2721 - 2727
(2015/09/01)
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- Visible light mediated efficient oxidative benzylic sp3 C-H to ketone derivatives obtained under mild conditions using O2
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A photooxygenation of benzylic sp3 C-H reaction has been demonstrated using O2 mediated by visible light. This protocol provides a simple and mild route to obtain ketones from benzylic sp3 C-H bonds. Various benzylic sp3 C-H bonds can be transformed into the desired ketone derivatives in moderate to good yields. The 18O2 labelling experiments demonstrated that the oxygen introduced into ketone originated from dioxygen. A plausible mechanism has been proposed accordingly.
- Yi, Hong,Bian, Changliang,Hu, Xia,Niu, Linbin,Lei, Aiwen
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supporting information
p. 14046 - 14049
(2015/09/15)
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- Cucurbit[7]uril promoting PdCl2-catalyzed cross-coupling reaction of benzyl halides and arylboronic acids in aqueous media
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The research provides a novel approach for producing diarylmethane derivatives using CB[7]-NaCl-PdCl2catalyzed Suzuki cross-coupling reaction of benzyl chloride derivatives and arylboronic acids in ethanol aqueous solution.
- Zhao, Guangkuan,Wang, Zhen,Wang, Ruixin,Li, Jingya,Zou, Dapeng,Wu, Yangjie
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supporting information
p. 5319 - 5322
(2015/01/16)
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- A highly efficient catalyst for Suzuki-Miyaura coupling reaction of benzyl chloride under mild conditions
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Diarylmethane derivatives, essential building blocks in organic synthesis, are usually synthesized through the traditional electrophilic substitution reaction i.e., Friedel-Crafts reaction, which suffers from the rearrangement and weak reactivity of aromatic compounds with deactivating/electron-withdrawing groups. The Suzuki-Miyaura coupling reaction of low-cost benzyl chloride as an alternative method overcomes these defects. Pd(ii) organometallic catalysts immobilized on the triphenylphosphine-functionalized microporous knitting aryl polymer (KAPs(Ph-PPh3)-Pd) as a novel heterogeneous catalyst was employed in Suzuki-Miyaura coupling reaction of benzyl chloride and exhibited excellent catalytic activity under mild conditions with a turnover frequency (TOF) up to 76 min-1 (4569 h-1). This work reveals that the microporous structure of the catalyst can rapidly adsorb substrates, consequently facilitating their interaction, and eventually promoting the catalytic efficiency. the Partner Organisations 2014.
- Guan, Zhenhong,Li, Buyi,Hai, Guoliang,Yang, Xinjia,Li, Tao,Tan, Bien
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p. 36437 - 36443
(2014/11/08)
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- Expedient iron-catalyzed coupling of alkyl, benzyl and allyl halides with arylboronic esters
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While attractive, the iron-catalyzed coupling of arylboron reagents with alkyl halides typically requires expensive or synthetically challenging diphosphine ligands. Herein, we show that primary and secondary alkyl bromides and chlorides, as well as benzyl and allyl halides, can be coupled with arylboronic esters, activated with alkyllithium reagents, by using very simple iron-based catalysts. The catalysts used were either adducts of inexpensive and widely available diphosphines or, in a large number of cases, simply [Fe(acac)3] with no added co- ligands. In the former case, preliminary mechanistic studies highlight the likely involvement of iron(I)-phosphine intermediates. More irons in the fire: Primary and secondary alkyl, benzyl and allyl halides were coupled with arylboronic esters by using very simple iron-based catalysts. These were either adducts of inexpensive and widely available diphosphines or, in a large number of cases, simply [Fe(acac)3] with no added co-ligands (see scheme; acac=acetylacetonate). In the former case, preliminary mechanistic studies highlight the likely involvement of low-coordinate iron(I)-phosphine intermediates.
- Bedford, Robin B.,Brenner, Peter B.,Carter, Emma,Carvell, Thomas W.,Cogswell, Paul M.,Gallagher, Timothy,Harvey, Jeremy N.,Murphy, Damien M.,Neeve, Emily C.,Nunn, Joshua,Pye, Dominic R.
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supporting information
p. 7935 - 7938
(2014/07/07)
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- Palladium-catalyzed benzylation of arylboronic acids with N,N-ditosylbenzylamines
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The palladium-catalyzed coupling of N,N-ditosylbenzylamines with arylboronic acids has been investigated, and the resulting diarylmethanes were obtained in high yields. Conversion of the amine to a N,N-ditosylimide group provided an efficient leaving group for the Pd-catalyzed benzylation of arylboronic acids.
- Yoon, Sangeun,Hong, Myeng Chan,Rhee, Hakjune
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p. 4206 - 4211
(2014/05/20)
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- Threefold and chemoselective couplings of triarylbismuths with benzylic chlorides and iodides using palladium catalysis
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This paper describes the palladium-catalyzed studies on threefold coupling of triarylbismuth reagents with benzylic chlorides and iodides. The optimized protocol conditions are operationally simple, delivering threefold coupling of a variety of triarylbismuths in combination with benzylic chlorides and iodides. The two optimized protocols allowed the synthesis of a diverse range of unsymmetrical diarylmethanes in an efficient manner. As part of this study, chemoselective transformation of benzylic chlorides and iodides was also achieved. This journal is the Partner Organisations 2014.
- Rao, Maddali L. N.,Dhanorkar, Ritesh J.
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p. 13134 - 13144
(2014/04/03)
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- Iridium-promoted, palladium-catalyzed direct arylation of unactivated arenes
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A Pd-catalyzed cross-coupling reaction between Cp*(PMe 3)IrBn2 and aryl halides was developed. Examining the scope of this reaction led to the discovery that Cp*(PMe 3)IrMeCl activates C-H bonds on arene substrates that undergo subsequent Pd-catalyzed cross-coupling with aryl iodides. This Ir-promoted, Pd-catalyzed direct arylation is notable for its distal selectivity on substituted arenes lacking directing groups or a particular electronic bias.
- Durak, Landon J.,Lewis, Jared C.
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supporting information
p. 620 - 623
(2014/03/21)
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- METHOD OF REGIOSELECTIVE SYNTHESIS OF SUBSTITUTED BENZOATES
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A method of synthesis of para-substituted benzoate esters and acids is provided, wherein the para-substituted regioisomer is obtained substantially free of the meta-substituted impurity, the method comprising contacting a coumalate ester or acid and an un activated alkene at elevated temperature in the presence of a metal oxidation catalyst and an oxidant. The metal oxidation catalyst can be palladium, such as palladium on carbon, and the oxidant can be the oxygen gas in ambient air. The reaction can be carlied out without solvent or in high boiling hydrocarbon solvents such as mesitylene. When the un activated alkene is a monosubstituted alkene, yields of at least about 50 or 60% of para-substituted ester and acid products, respectively, are obtained, substantially free of the regioisomelic meta-substituted impurity.
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Page/Page column 11; 18; 19
(2013/03/26)
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- Indium(III) triflate - A catalyst for greener aromatic alkylation reactions
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An environmentally friendly method for alkylating aromatic compounds with simple alcohols in the presence of a catalytic amount of indium(III) triflate is reported. Ionic liquids are used as solvents and energy-efficient heating is provided by microwave radiation. Good yields are obtained with benzyl, secondary, and tertiary alcohols. Simple primary alcohols are not effective alkylating agents under these conditions. With tertiary alcohols, activated aromatic compounds such as toluene and anisole must be used to obtain good yields. The catalyst, which is immobilized in a water-insoluble ionic liquid, can be easily recycled without significant loss of activity.
- Mack, Ryan,Askins, Grant,Lowry, Jacob,Hurley, Nathan,Reeves, Perry C.
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p. 1262 - 1265
(2014/01/06)
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- A Palladium Bipyridyl Complex Grafted onto Nanosized MCM-41 as a Heterogeneous Catalyst for Negishi Coupling
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The Negishi coupling of aryl bromides or acyl chlorides with organozinc chlorides catalyzed by a palladium bipyridyl complex anchored on nanosized mobile crystalline material 41 (MCM-41) were investigated. The reactions proceeded smoothly with a very low catalyst loading in THF at 70°C for electron-deficient aryl bromides, which gave good to high yields of the Negishi coupling products. However, reactions in toluene at 110°C were required if electron-rich aryl bromides were employed. For acyl chlorides, the reactions could be performed in THF at 50°C and the corresponding ketones and ynones were obtained in high yields. After centrifugation, it was possible to easily recover the supported catalyst from the reaction mixture, and this could be reused several times without any retreatment or regeneration with only a slight decrease in activity.
- Wu, Wei-Yi,Lin, Tze-Chiao,Takahashi, Tamotsu,Tsai, Fu-Yu,Mou, Chung-Yuan
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p. 1011 - 1019
(2013/05/09)
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- Nickel-catalyzed cross couplings of benzylic ammonium salts and boronic acids: Stereospecific formation of diarylethanes via C-N bond activation
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We have developed a nickel-catalyzed cross coupling of benzylic ammonium triflates with aryl boronic acids to afford diarylmethanes and diarylethanes. This reaction proceeds under mild reaction conditions and with exceptional functional group tolerance. Further, it transforms branched benzylic ammonium salts to diarylethanes with excellent chirality transfer, offering a new strategy for the synthesis of highly enantioenriched diarylethanes from readily available chiral benzylic amines.
- Maity, Prantik,Shacklady-Mcatee, Danielle M.,Yap, Glenn P. A.,Sirianni, Eric R.,Watson, Mary P.
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supporting information
p. 280 - 285
(2013/02/25)
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- Exploiting boron-zinc transmetallation for the arylation of benzyl halides: What are the reactive species?
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One step Beyond: The transmetallation reactions of ArB(OH)2 and Ar3B3O3 with Et2Zn are far more complicated than previously supposed, with solvent-dependent equilibria between ArB(OY)2 at one side and [RZn(solv)3][BR4] at the other (see picture). While the role of the highly reactive organozinc cation has not been implicated before, its importance for the activation of an otherwise sluggish class of electrophiles is shown. Copyright
- Bedford, Robin B.,Gower, Nicholas J.,Haddow, Mairi F.,Harvey, Jeremy N.,Nunn, Joshua,Okopie, Rukeme A.,Sankey, Rosalind F.
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supporting information; experimental part
p. 5435 - 5438
(2012/07/03)
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- Suzuki-Miyaura cross-coupling of benzylic bromides under microwave conditions
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A procedure for benzylic Suzuki-Miyaura cross-coupling under microwave conditions has been developed. These conditions allowed for heterocyclic compounds to be coupled. Optimum conditions found were Pd(OAc)2, JohnPhos as the catalyst and ligand
- McDaniel, Steven W.,Keyari, Charles M.,Rider, Kevin C.,Natale, Nicholas R.,Diaz, Philippe
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supporting information; experimental part
p. 5656 - 5658
(2011/11/06)
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- Aromatics from pyrones: Para-substituted alkyl benzoates from alkenes, coumalic acid and methyl coumalate
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The Diels-Alder reaction of coumalic acid and methyl coumalate with unactivated alkenes provides only para-substituted adducts in good yield.
- Kraus, George A.,Riley, Sean,Cordes, Travis
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experimental part
p. 2734 - 2736
(2011/11/06)
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- Dichloro-bis(aminophosphine) complexes of palladium: Highly convenient, reliable and extremely active suzuki-miyaura catalysts with excellent functional group tolerance
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Dichloro-bis(aminophosphine) complexes are stable depot forms of palladium nanoparticles and have proved to be excellent SuzukiMiyaura catalysts. Simple modifications of the ligand (and/or the addition of water to the reaction mixture) have allowed their formation to be controlled. Dichlorobis[1- (dicyclohexylphosphany1)piperidine]palladium (3), the most active catalyst of the investigated systems, is a highly convenient, reliable, and extremely active Suzuki catalyst with excellent functional group tolerance that enables the quantitative coupling of a wide variety of activated, nonactivated, and deactivated and/or sterically hindered functionalized and heterocyclic aryl and benzyl bromides with only a slight excess (1.1-1.2 equiv) of arylboronic acid at 80°C in the presence of 0.2 mol % of the catalyst in technical grade toluene in flasks open to the air. Conversions of >95% were generally achieved within only a few minutes. The reaction protocol presented herein is universally applicable. Side-products have only rarely been detected. The catalytic activities of the aminophosphine-based systems were found to be dramatically improved compared with their phosphine analogue as a result of significantly faster palladium nanoparticle formation. The decomposition products of the catalysts are dicyclohexylphosphinate, cyclohexylphosphonate, and phosphate, which can easily be separated from the coupling products, a great advantage when compared with non-water-soluble phosphine-based systems.
- Bolliger, Jeanne L.,Frech, Christian M.
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supporting information; experimental part
p. 4075 - 4081
(2010/08/05)
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- Simple mixed Fe-Zn catalysts for the Suzuki couplings of tetraarylborates with benzyl halides and 2-halopyridines
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Employing co-catalytic zinc reagents facilitates the iron-catalysed Suzuki cross-coupling of tetraarylborates with both benzyl and 2-heteroaryl halides.
- Bedford, Robin B.,Hall, Mark A.,Hodges, George R.,Huwe, Michael,Wilkinson, Mark C.
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supporting information; experimental part
p. 6430 - 6432
(2010/03/03)
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- Synthesis of functionalised diarylmethanes via a cobalt-catalysed cross-coupling of arylzinc species with benzyl chlorides
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A new cobalt-catalysed reductive coupling of aryl halides with benzyl chlorides is reported; a variety of diarylmethanes can be prepared in good to excellent yields under mild reaction conditions using CoBr2 as catalyst and Zn dust; this new cobalt-catalysed coupling represents a practical and interesting alternative to previously known methods for the synthesis diarylmethanes. The Royal Society of Chemistry.
- Amatore, Muriel,Gosmini, Corinne
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supporting information; experimental part
p. 5019 - 5021
(2009/06/05)
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- O-benzyl trichloroacetimidates having electron-withdrawing substituents in acid-catalyzed diarylmethane synthesis
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Reaction of O-benzyl trichloroacetimidates having electron-withdrawing substituents with arenes in the presence of catalytic amounts of TMSOTf gave the corresponding diarylmethanes in good to excellent yields. Georg Thieme Verlag Stuttgart.
- Zhang, Jianjun,Schmidt, Richard R.
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p. 1729 - 1733
(2008/02/04)
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- Organic compounds
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Novel compounds that inhibit the binding of the Smac protein to Inhibitor of Apoptosis Proteins (IAPs) of the formula I
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Page/Page column 12; 24
(2008/06/13)
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- Cross-coupling of benzylic acetates with arylboronic acids: One-pot transformation of benzylic alcohols to diarylmethanes
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Benzylic acetates reacted with arylboronic acids in the presence of a DPEphos-[Pd(η3-C3H5)Cl]2 catalyst when tert-amyl alcohol was used as a solvent, and the catalytic cross-couplings produced diarylmethanes in high yields (up to 94% isolated yield). The Royal Society of Chemistry 2005.
- Kuwano, Ryoichi,Yokogi, Masashi
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p. 5899 - 5901
(2007/10/03)
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