Iron-Catalyzed Reductive Deuteration of Ketones and Imines.

An iron-catalyzed reductive deuteration has been developed for the efficient synthesis of deuterated alcohols and amines. This method employs cost-effective DMSO-d6 as the deuterium source and (Bpin)2 as the reductant, achieving high levels of D-incorporation (up to 99%) across various substrates, including aryl alkyl ketones, diaryl ketones, aryl aldimines, and aryl ketimines. Mechanistic studies indicate that the ionic iron-boron intermediate generated under conditions of excess base, high temperature, and polar solvents serves as a crucial intermediate for reducing C═O and C═N bonds to form radical anions through single electron transfer (SET), which then undergo deuterium atom transfer (DAT) to afford the reductive deuteration products.