Construction of Axially Chiral Styrenes Linking an Indole Moiety by Chiral Phosphoric Acid.

Herein we report a chiral phosphoric acid-catalyzed intermolecular C2 Friedel-Crafts alkylation reaction between ortho-alkynylnaphthols and various 3-substituted indoles, affording axially chiral alkenes with up to 93% yields (E/Z > 20:1) and up to 98% ee under mild reaction condition. Other substituted indole derivatives could be also tolerated in this system, giving the corresponding axially chiral alkenes with high yields and in excellent enantioselectivity.