Access to C─N and N─N Axially Chiral Pyridinones via NHC‐Catalyzed Dynamic Kinetic Resolution of Rotationally Restricted Cyclic Imides

Abstract

ABSTRACT Atropisomers bearing C─N or N─N axes are an important class of chiral molecules, yet stereoconvergent strategies for accessing these compounds using organocatalytic techniques remain limited. Herein, we report the N‐heterocyclic carbene (NHC)‐catalyzed dynamic kinetic resolution (DKR) of rotationally restricted cyclic imides via (3 + 3) annulation with enals under oxidative conditions for the synthesis of C─N or N─N axially chiral pyridinones. Mechanistic experiments shed light on keto‐enol tautomerism in cyclic imides, which serves as the operative mode of enantiomer interconversion. This transformation furnishes C─N/N─N axially chiral frameworks bearing a remote stereogenic center in high yields with excellent enantioselectivity (up to 99:1 er) and good diastereocontrol. Rotation barrier studies confirm the high configurational stability of the products. Reactions conducted using pre‐formed carbenes provide information on DKR operating in the present case over the competing desymmetrization pathway.