Atroposelective synthesis of N–N axially chiral pyrrolylamides by combined-acid catalytic Paal–Knorr reaction†

Abstract

A general and efficient method for the construction of enantiomerically pure N–N axially chiral pyrrolylamides by utilizing the catalytic asymmetric Paal–Knorr reaction has been developed. The key to success is the use of the binary-acid catalytic system involving the dramatic synergistic effect of a Lewis acid and a chiral phosphoric acid for achieving effective stereocontrol.