Enantioselective synthesis of axially chiral carbamates and amides with carbon dioxide via copper catalysis

Abstract

Catalytic asymmetric conversion of carbon dioxide (CO₂) into valuable chiral compounds is one of the most challenging research topics in the field of CO₂ utilization. Although great progress has recently been made in the transformation of CO₂ into centrally chiral compounds, the assembly of axially chiral molecules with CO₂ has seldom been explored. Herein, we report a copper-catalyzed asymmetric ring-opening reaction of cyclic diaryliodoniums with CO₂ and amines, providing direct access to a range of axially chiral carbamates with high yields and enantioselectivities. Moreover, by using the strategy of merging the ring-opening reaction with a remote anionic Fries rearrangement, the synthesis of axially chiral amides was also achieved. The advantages of these methods include mild conditions, broad substrate scope and excellent enantioselectivity. Their synthetic applications were demonstrated by late-stage modification of natural products and drug molecules as well as by the diverse transformations of the axially chiral products into various useful chiral biaryls.