Deracemization through Sequential Photoredox‐Neutral and Chiral Brønsted Acid Catalysis

Abstract

AbstractCatalytic deracemization is an ideal synthetic strategy due to its formally perfect atom utilization. Asymmetric photocatalysis has been appreciated as a promising tool to accomplish this attractive reaction pattern in an economical fashion, but it remains underdeveloped. Here, we report a new platform based on photoredox‐neutral catalysis, allowing efficient and modular optical enrichment of α‐amino esters and other valuable analogues. Two single‐electron transfer processes between the photocatalyst and the substrates serve to provide the key prochiral intermediates, and the chiral Brønsted acid catalyst mediates enantioselective protonation to reconstitute a stereogenic C−H bond. The efficiency of deracemization is determined by the enantiofacial differentiation effect during the stereocentre‐forming step.