The RhCl3· 3H2O/i-Pr2NEt-catalyzed [2+ 2+ 2] cyclotrimerization of alkynes has been achieved. The reaction can be widely used for various alkynes and provides tri-or hexa- substituted benzenes regioselectively in high yields. The [2+ 2+ 2] cycloaddition of diynes and alkynes is also developed, and it affords benzene derivatives in moderate to high yields.
