Remote Copper-Catalyzed Atroposelective Synthesis of N–N Axially Chiral Compounds Bearing Minimally Different Alkyl Groups

Abstract

Herein, we report a copper-catalyzed remote asymmetric [4+1] annulation/aromatization between yne-allylic esters and N-aminoindoles, providing axially chiral N,N′-indolepyrroles that contain sterically comparable ortho substituents, such as methyl and ethyl. This reaction proceeds smoothly under mild conditions, affording products with excellent regio- and enantioselectivities while demonstrating broad functional group compatibility. The synthetic utility of this approach is further showcased through the late-stage modification of biologically relevant scaffolds. Additionally, preliminary mechanistic investigations indicate that remote nucleophilic substitution is the enantio-determining step.