Design of Planar Chiral Phosphoric Acids with a [2.2]Paracyclophanyl Backbone as Organocatalysts for the Highly Enantioselective Aza-Friedel-Crafts Reaction.

Abstract

A new type of robust planar chiral phosphoric acid bearing a [2.2]paracyclophane scaffold was synthesized and shown to be an optimal catalyst in asymmetric aza-Friedel-Crafts reactions for the first synthesis of enantioenriched styryl indolylmethanamine derivatives in good yields with excellent enantioselectivities (93->99% ee) under 0.5-1 mol % catalyst loading.