Enantioselective Synthesis of Unsymmetrical Triarylmethanes by Chiral Bronsted Acids

Chiral Bronsted acid catalyzed Friedel-Crafts alkylation of electron-rich arenes with (3-indolyl)methanamines has been realized to provide an efficient synthesis of enantioenriched unsymmetrical triarylmethanes. With 5 mol-% of a newly developed chiral phosphoric acid, the enantioenriched unsymmetrical triarylmethanes were obtained in excellent yields with up to 91 % ee.