Copper-Catalyzed Desymmetric Alkyne–Azide Cycloaddition to Access Axially Chiral Biaryls

Abstract

Axially chiral biaryls are an important class of structural units widely used in natural product synthesis, drug design, and as ligands for asymmetric catalysis. Although significant progress has been made in the synthesis of axially chiral biaryls, some of them are still limited to narrow substrate ranges, low efficiency, and moderate stereocontrol. Herein, we describe a highly efficient route to prepare atropisomeric biaryls with triazole and alkyne modules through the desymmetrization of prochiral dialkynyl diaryls utilizing chiral cyclobutyl-bridge box ligands in conjunction with copper salts. The process has mild conditions, good functional-group tolerance, and can obtain a wide array of valuable axially chiral biaryl derivatives with good to excellent yields and enantioselectivities.