Rhodium(I)‐Catalyzed [4+1] Cycloaddition Reactions of α,β‐Unsaturated Imines with Terminal Alkynes for the Preparation of Pyrrole Derivatives

Abstract

Rhodium vinylidene intermediates are characteristic for the title reaction (see scheme; coe=cyclooctene, cy=cyclohexyl). This reaction proceeds by the nucleophilic addition of the nitrogen atom of the imine to the rhodium vinylidene complex to give a zwitterionic intermediate, which undergoes intramolecular cyclization to afford the corresponding pyrrole.