NbCl₃-Catalyzed Three-Component [2 + 2 + 2] Cycloaddition Reaction of Terminal Alkynes, Internal Alkynes, and Alkenes to 1,3,4,5-Tetrasubstituted 1,3-Cyclohexadienes

Abstract

Three-component [2 + 2 + 2] cycloaddition of terminal alkynes, internal alkynes, and terminal alkenes is achieved using an NbCl(3)(DME) catalyst, leading to 1,3,4,5-substituted 1,3-cyclohexadienes in excellent yields with high chemo- and regioselectivity.