Department of Chemistry, Graduate School of Engineering Science , Osaka University , Toyonaka , Osaka 560-8531 , Japan.
Department of Chemistry , University of Minnesota-Twin Cities , 207 Pleasant Street SE , Minneapolis , Minnesota 55455 , United States.
J Am Chem Soc. 2019 Mar 13;141(10):4194-4198. doi: 10.1021/jacs.8b13390. Epub 2019 Feb 11.
The combination of VCl(THF) and N, N-bis(trimethylsilyl)aniline (1a) is an efficient catalyst for the [2+2+1] coupling reaction of alkynes and azobenzenes, giving multisubstituted pyrroles. A plausible reaction mechanism involves the generation of a mono(imido)vanadium(III) species as an initiation step, where 1a served as an imido source with concomitant release of 2 equiv of ClSiMe, followed by a reaction with azobenzene to form a catalytically active bis(imido)vanadium(V) species via N═N bond cleavage.
VCl(THF) 和 N, N-双(三甲基硅基)苯胺（1a）的组合是炔烃和偶氮苯的 [2+2+1] 偶联反应的有效催化剂，生成多取代吡咯。一个合理的反应机制涉及单（亚氨基）钒（III）物种的生成作为引发步骤，其中 1a 作为亚氨基源，同时释放 2 当量的 ClSiMe3，随后与偶氮苯反应，通过 N═N 键断裂形成催化活性的双（亚氨基）钒（V）物种。
