Visible Light-Promoted Thiobenzoic Acid-Catalyzed Deuteration of Alkylamines and Alkylarenes

A mild and efficient photocatalytic protocol for the α-deuteration of aliphatic amines has been developed using thiobenzoic acid as the HAT catalyst without the extra photocatalyst. This new method can be applied to a variety of aliphatic amines, amides, and carbamates with high deuterium incorporations and isolated yields. Alkylated arenes are also amenable to this reaction, as the deuteration occurs regioselectively at the benzylic positions. Deuteration of active pharmaceutical ingredients is also demonstrated. Primary mechanistic studies indicate an hydrogen atom transfer pathway for this hydrogen isotope exchange process.