Conjugate Aminocyclization Catalyzed by a Bismuthinidene

Abstract

We disclose how an N,C,N-bismuthinidene is able to promote an intramolecular conjugate amination that affords cyclic carbamates in 91–97% yields. The reaction proceeds at room temperature in short reaction times, requiring a remarkably low loading of a bismuth(I) complex (0.1 mol%) without the need of an additional Brønsted base. Preliminary mechanistic studies suggest that the reaction takes place through a polar pathway involving the conjugate addition of the nucleophilic bismuthinidene, followed by an intramolecular aza-Michael reaction.