InCl(3)-catalyzed asymmetric aza-Friedel-Crafts reaction of indoles with imines generated from O-pivaloylated beta-D-galactosylamine.

The highly diastereoselective InCl(3)-catalyzed aza-Friedel-Crafts reaction of substituted indoles with aldimines generated from Kunz's amine was studied. The reaction afforded the desired product in good to high yields with up to >19:1 diastereoselective ratios. The O-pivaloylated beta-D-galactosyl moiety could not be cleaved under the traditional acidic conditions. It was removed successfully after unmasking of the O-pivaloyl groups using MeOH/NaOMe and treatment with HOAc/H(2)O subsequently, to yield the 3-indolyl aryl methanamine derivatives in high optical purity.