Regioselective synthesis of 1,3,5-substituted benzenes via the InCl(3)/2-iodophenol-catalyzed cyclotrimerization of alkynes.

A novel indium(III)-catalyzed cyclotrimerization of alkynes in the presence of 2-iodophenol gave 1,3,5-substituted benzenes in excellent yields with complete regioselectivity. The reaction condition is tolerant to air, and atom economical, in accordance with the concept of modern green chemistry. This method provides a rapid and efficient access to 1,3,5-substituted benzenes.