Visible-Light-Mediated Photocatalytic Deracemization.

Asymmetric catalysis has long been recognized as a powerful tool for the synthesis of enantioenriched molecules. In addition to precise enantiocontrol, high-atom economy, which is crucial for practicality, has always been pursued by chemists in the development of methodologies. Consequently, deracemization, the direct conversion of a racemic compound to one of its enantiomers, and thus characterized by a 100 % atom efficiency, has attracted increasing interest. Recently, visible-light-driven photocatalysis has been demonstrated to be a promising platform for the development of deracemization. Central to its success is its ability to efficiently overcome the prevailing kinetic issues in chemical transformations and the intrinsic thermodynamic challenges, which typically require the use of additional stoichiometric reagents, thus undermining the original advantages. In this review, the advances in this attractive area are systematically summarized and discussed, with examples organized according to the different modalities of energy transfer and single-electron transfer in photocatalysis.