and cyclohexane) and the relative rate of O—H insertion into methanol to stereospecific cyclopropanation of the olefin to C—H insertion into cyclohexane are calculated from the ratios of products and substrates. It is found (i) that the reactivities of the substrates decrease in the order of methanol, olefin and cyclohexane and (ii) that electron-donating substituents generally lead to reaction with
sphinomethyl)cyclopentane as a catalyst, a range of aryl bromides and chlorides undergoes Suzuki cross-coupling with alkylboronic acids in good yields. Several alkyl substituents such as ethyl, n-butyl, n-octyl, isobutyl or 2,2-dimethylpropyl on the alkylboronic acids have been successfully used. The functional group tolerance on the arylhalide is remarkable; substituents such as fluoro, methyl, methoxy
通过使用[PdCl(C 3 H 5)] 2 /顺式,顺式,顺式-1,2,3,4-四(二苯基膦甲基)环戊烷作为催化剂,一系列芳基溴化物和氯化物进行铃木交叉偶联与烷基硼酸的收率很好。几个烷基取代基,例如乙基,正丁基,n已经成功地使用了烷基硼酸上的-辛基,异丁基或2,2-二甲基丙基。芳基卤对官能团的耐受性显着;可以容忍诸如氟,甲基,甲氧基,乙酰基,甲酰基,苯甲酰基,硝基或腈之类的取代基。此外,该催化剂即使在位阻芳基溴的反应中也可以低负荷使用。
Highly Efficient, General Procedure for the Preparation of Alkylzinc Reagents from Unactivated Alkyl Bromides and Chlorides
作者:Shouquan Huo
DOI:10.1021/ol0272693
日期:2003.2.1
[reaction: see text] Alkylzinc bromides have been efficiently prepared by the direct insertion of zinc metal (dust, powder, granule, shot), activated with 1-5 mol % I(2), into alkyl bromides in a polar aprotic solvent. The zinc reagents thus formed undergo Ni- and Pd-catalyzed cross-coupling with aryl halides to produce functionalized alkylarenes in excellent yields.
Cobalt-catalyzed cross-coupling of Umpolung carbonyls with alkyl halides under mild conditions
作者:Ruofei Cheng、Graham de Ruiter、Chao-Jun Li
DOI:10.1039/d2cc04302e
日期:——
dominated by palladium and nickel catalysts, cobalt-based catalysts have shown unique advantages for such cross-coupling reactions in terms of higher catalyticactivity and lower toxicity. Herein, we describe a novel cobalt-catalyzed alkyl–alkyl cross-coupling reaction of hydrazone with alkylhalides under mild reaction conditions, where the use of a PNP-type pincerligand is essential for catalysis
Deoxygenative coupling of alcohols with aromatic nitriles enabled by direct visible light excitation
作者:Yanjiao Xiong、Xuesong Wu
DOI:10.1039/d3ob01676e
日期:——
A general and practical protocol is presented for visible-light-driven deoxygenativecoupling of alcohols with aromatic nitriles in the absence of external photocatalysts. Utilizing a hydroxyl activation strategy with carbon disulfide, this C(sp3)–C(sp2) constructing platform accommodates a broad scope of alcohols and aryl nitriles to deliver various alkyl-substituted arenes. Mechanism studies show