Light-Induced CH Arylation of (Hetero)arenes by In Situ Generated Diazo Anhydrides
作者:David Cantillo、Carlos Mateos、Juan A. Rincon、Oscar de Frutos、C. Oliver Kappe
DOI:10.1002/chem.201502357
日期:2015.9.7
catalyst‐free CH arylation methodology for the preparation of bi(hetero)aryls by the one‐pot reaction of anilines with tert‐butyl nitrite and (hetero)arenes under neutral conditions. The key step in this procedure is the in situ formation and subsequent photochemical (>300 nm) homolytic cleavage of a transient diazo anhydride intermediate. The generated aryl radical then efficiently reacts with a (hetero)arene
Transition‐Metal‐Free Synthesis of Heterobiaryls through 1,2‐Migration of Boronate Complex
作者:Swagata Paul、Kanak Kanti Das、Samir Manna、Santanu Panda
DOI:10.1002/chem.201904761
日期:2020.2.11
carbon atom. Subsequent oxidation of the intermediate boronic ester afforded heterobiaryls in good yield. A comprehensive 11 B 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
通过使用锂化的杂环,芳基或杂芳基硼酸酯和亲电卤素源,通过无过渡金属的sp2-sp2交叉偶联策略,可以实现多种杂芳基芳基化合物的合成。杂二芳基的构建是通过亲电活化芳基-杂芳基硼酸酯络合物进行的,这引发了1,2-从硼向碳原子的迁移。中间体硼酸酯的随后氧化以良好的产率提供了杂联二芳基。已经进行了全面的11 B NMR研究以支持该机理。在没有过渡金属的情况下,两个亲核交叉偶联伙伴之间的交叉偶联显示了可靠的歧管,可以以高收率获得杂二芳基。呋喃,噻吩,苯并呋喃,苯并噻吩和吲哚等各种杂环具有良好的耐受性。最后,
Visible light mediated desilylative C(sp<sup>2</sup>)–C(sp<sup>2</sup>) cross-coupling reactions of arylsilanes with aryldiazonium salts under Au(<scp>i</scp>)/Au(<scp>iii</scp>) catalysis
作者:Indradweep Chakrabarty、Manjur O. Akram、Suprakash Biswas、Nitin T. Patil
DOI:10.1039/c8cc03925a
日期:——
Desilylative C(sp2)–C(sp2) cross-coupling reactions of arylsilanes with aryldiazonium salts under Au(I)/photoredox catalysis have been reported. The addition of Cu-salts as catalysts was found to be crucial for the success of this transformation.
Conditions for the palladium-catalyzed directarylation of a wide range of heterocycles with aryl bromides are reported. Those conditions employ a stoichiometric ratio of both coupling partners, as well as a substoichiometric quantity of pivalicacid, which results in significantly faster reactions. An evaluation of the influence of the nature of the aryl halide has also been carried out.
Three-component 2-aryl substituted benzothiophene formation under transition-metal free conditions
作者:Pengcheng Jiang、Xingzong Che、Yunfeng Liao、Huawen Huang、Guo-Jun Deng
DOI:10.1039/c6ra07730g
日期:——
A base-mediated 2-aryl substituted benzothiopheneformation from 2-bromobenzene aldehydes, benzylic esters and elemental sulfur under transition-metal-free conditions is described. Various 2-aryl substituted benzothiophene were efficiently obtained under mild conditions.