Asymmetric synthesis of axially chiral N,N′-carbazolepyrrole via copper-catalyzed Friedel–Crafts reaction

Abstract

N–N atropisomers are commonly found in natural products and pharmaceuticals. Herein, we report a copper-bisoxazoline-catalyzed Friedel–Crafts reaction that enables the first enantioselective synthesis of N,N′-carbazole-pyrrole rings. This method demonstrates practical advantages with mild reaction conditions, an atom-economic process, high enantioselectivity and very broad substrate scope. Additionally, its scalability and versatility are showcased through gram-scale synthesis and diverse transformation applications.