Bis(imido)vanadium(V)-Catalyzed [2+2+1] Coupling of Alkynes and Azobenzenes Giving Multisubstituted Pyrroles
作者:Kento Kawakita、Evan P. Beaumier、Yuya Kakiuchi、Hayato Tsurugi、Ian A. Tonks、Kazushi Mashima
DOI:10.1021/jacs.8b13390
日期:2019.3.13
[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 ClSiMe3, followed by a reaction with azobenzene to form a catalytically active bis(imido)vanadium(V) species via N═N bond cleavage
VCl3(THF)3 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生成单(亚氨基)钒(III)物质作为引发步骤,其中 1a 作为亚氨基源,同时释放 2 当量的 ClSiMe3,然后与偶氮苯反应形成催化活性物质通过 N=N 键断裂形成双(亚氨基)钒(V)物质。