Ni‐Catalyzed Regioselective Cyclotrimerization of Internal Esteryl Alkynes towards Polysubstituted Benzene Rings

Abstract Transition‐metal‐catalyzed [2+2+2] cycloaddition of alkynes is a core synthetic approach to benzene rings. Herein we describe an efficient system based on inexpensive nickel catalyst and phosphine ligand that facilitate cyclotrimerization of various internal esteryl alkynes. The regioselectivity of the protocol was precisely controlled, and a series of polysubstituted benzene rings mainly composed of 1,2,4‐isomers were provided.