Enantioselective synthesis of (3-indolyl)glycine derivatives via asymmetric Friedel-Crafts reaction between indoles and glyoxylate imines

Chiral phosphoric acid-catalyzed enantioselective Friedel-Crafts reaction of indoles with ethyl glyoxylate imines was developed. With 10 mol % of the catalyst, the Friedel-Crafts reactions between a wide range of indoles and imines have been carried out, affording optically active (3-indolyl)glycine derivatives with excellent yields and high enantioselectivities (up to 87% ee).