Nickel-Catalyzed Reductive Cross-Coupling of Benzyl Halides with Aryl Halides
作者:Qun Qian、Hegui Gong、Qingchen Zhang、Xuan Wang
DOI:10.1055/s-0035-1562442
日期:——
Abstract Systematic studies of the coupling of benzylic with aryl halides are presented. The optimized reaction conditions for electron-deficient aryl halides cannot be applied to the electron-rich or neutral counterparts, and vice versa. The excellent functional group tolerance and broad substrate scope may enable the current work to be useful for the construction of diaryl methane products. Systematic
Mild Negishi Cross-Coupling Reactions Catalyzed by Acenaphthoimidazolylidene Palladium Complexes at Low Catalyst Loadings
作者:Zelong Liu、Ningning Dong、Mizhi Xu、Zheming Sun、Tao Tu
DOI:10.1021/jo400803s
日期:2013.8.2
3a exhibited extremely high catalytic activity toward Negishicross-coupling of alkylzinc reagents with a wide range of (hetero)arylhalides under mild reaction conditions within 30 min. Besides a great number of bromoarenes, various less expensive and inactive (hetero)aryl chlorides were coupled successfully with the alkyl- and arylzincreagents, in which active functional groups (such as -NH2) were
考虑到衍生自π-延伸的咪唑鎓盐的亚烷基的强大的σ-供体性质有利于提高所得钯N-杂环卡宾配合物的催化活性,因此制备了具有健壮的并咪唑-亚烷基钯配合物3a - c,具有不同的大取代基团通过在纯净的3-氯吡啶中与PdCl 2和K 2 CO 3加热,从相应的啶咪唑氯化物中得到满意的收率。即使在催化剂负载量低至0.25 mol%的情况下,配合物3a在温和的反应条件下,在30分钟内显示出对烷基锌试剂与各种(杂)芳基卤化物的Negishi交叉偶联极高的催化活性。除了大量的溴代芳烃外,还成功地将各种较便宜且不活泼的(杂)芳基氯化物与烷基-和芳基锌试剂偶联,其中具有活性官能团(例如-NH 2))即使在无保护的一锅双偶转换中也具有良好的耐受性。此外,在与仲烷基锌试剂偶联的情况下,有效抑制了导致异构化的线性产物的不希望的β-氢化物消除。通过杂芳基锌试剂和杂环氯代芳烃的偶联,该催化剂体系还显示出在杂二芳基结构方面
Photo-Ni-Dual-Catalytic C(sp<sup>2</sup>)–C(sp<sup>3</sup>) Cross-Coupling Reactions with Mesoporous Graphitic Carbon Nitride as a Heterogeneous Organic Semiconductor Photocatalyst
作者:Jagadish Khamrai、Indrajit Ghosh、Aleksandr Savateev、Markus Antonietti、Burkhard König
DOI:10.1021/acscatal.9b05598
日期:2020.3.20
nitride (mpg-CN) and a homogeneous nickel catalyst with visible-light irradiation at room temperature affords the C(sp2)–C(sp3) cross-coupling of aryl halides and potassium alkyl trifluoroborates by single electron transmetallation. Like the homogeneously catalyzed protocol, the reaction is compatible with a variety of functional groups including electron-donating and electron-withdrawing aryl and heteroaryl
作者:Sheng-Peng Jiang、Xiao-Yang Dong、Qiang-Shuai Gu、Liu Ye、Zhong-Liang Li、Xin-Yuan Liu
DOI:10.1021/jacs.0c09125
日期:2020.11.18
A copper-catalyzed enantioconvergent Suzuki-Miyaura C(sp3)-C(sp2) cross-coupling of various racemic alkyl halides with organoboronate esters has been established in high enantioselectivity. Critical to the success is the use of a chiral cinchona alkaloid-derived N,N,P-ligand for not only enhancing the reducing capability of copper catalyst to favor a stereoablative radical pathway over a stereospecific
The direct arylation of allylic sp3 C–H bonds via organic and photoredox catalysis
作者:James D. Cuthbertson、David W. C. MacMillan
DOI:10.1038/nature14255
日期:2015.3.5
particular, the direct arylation of non-functionalized allylic systems would enable access to a series of known pharmacophores (molecular features responsible for a drug’s action), though a general solution to this long-standing challenge remains elusive. Here we report the use of both photoredox and organic catalysis to accomplish a mild, broadly effective direct allylic C–H arylation. This C–C bond forming
未活化的 sp3 C-H 键的直接功能化仍然是合成有机化学家面临的最具挑战性的问题之一。这种转变的吸引力来自于它们通过简单和其他惰性结构单元的耦合促进复杂有机分子构建的能力,而不会引入无关的官能团。尽管最近做出了显着的努力,但事实证明,为 sp3 C-H 键参与 C-C 键形成反应建立一般和温和的策略是困难的。在此背景下,发现能够以催化方式直接使烯丙基甲基、亚甲基和次甲基碳官能化的化学转化是当务之急。尽管烯丙基 C-H 键的直接氧化和胺化方案(即,C-H 键,其中相邻的碳参与 C = C 键)已经广泛建立,烯丙基底物在 C-C 键形成反应中的参与迄今为止需要使用预官能化的偶联伙伴。特别是,非功能化烯丙基系统的直接芳基化将能够获得一系列已知的药效团(负责药物作用的分子特征),尽管解决这一长期挑战的通用解决方案仍然难以捉摸。在这里,我们报告了使用光氧化还原和有机催化来完成温和、广泛有效的直接烯丙基