Cobalt-mediated cross-coupling reactions of primary and secondary alkyl halides with 1-(trimethylsilyl)ethenyl- and 2-trimethylsilylethynylmagnesium reagents
Cobalt-mediated cross-coupling reactions of primary and secondary alkyl halides with 1-(trimethylsilyl)ethenyl- and 2-trimethylsilylethynylmagnesium reagents
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DOI：
10.1021/ol0611144
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发表时间：
2006-07-06
期刊：
影响因子：
5.2
通讯作者：
Oshima, Koichiro
中科院分区：
文献类型：
--
作者：
Ohmiya, Hirohisa;Yorimitsu, Hideki;Oshima, Koichiro
[图解]本文分别描述了1-(三甲基硅基)乙炔基溴化镁和2-(三甲基硅基)乙炔基溴化镁在钴催化下的交叉偶联反应。钴体系允许使用仲烷基卤化物和伯烷基卤化物作为底物。这些反应提供了烷基-烯基和烷基-炔基键的容易形成。反应机理包括单电子从钴络合物转移到卤化烷基生成相应的烷基自由基。因此，钴体系使得6-卤代-1-己烯衍生物的顺序自由基环化/烯基化和环化/炔化反应成为可能。
[GRAPHICS]This paper describes cobalt-mediated cross-coupling reactions of alkyl halides with 1-(trimethylsilyl) ethenylmagnesium bromide and 2-(trimethylsilyl) ethynylmagnesium bromide, respectively. The cobalt system allows for employing secondary as well as primary alkyl halides as the substrates. The reactions offer facile formations of alkyl-alkenyl and alkyl-alkynyl bonds. The reaction mechanism would include single-electron transfer from a cobalt complex to alkyl halide to generate the corresponding alkyl radical. The cobalt system thus enables sequential radical cyclization/alkenylation and cyclization/alkynylation reactions of 6-halo-1-hexene derivatives.