Continuous-Flow Asymmetric Photocatalysis for the Synthesis of Natural and Unnatural α-Amino Acid Derivatives

Enantiomerically enriched α-amino acids and their derivatives are important building blocks, widely used in the pharmaceutical industry, drug research, and materials science. Therefore, the development of straightforward and versatile synthetic methods remains highly desirable. Herein, we disclose a photochemical enantioselective addition of alkyl radicals to α-imino esters, mediated by a chiral-at-metal rhodium catalyst under continuous flow conditions. This strategy provides rapid and direct access to enantioenriched derivatives of both natural and unnatural α-amino acids, achieving yields of up to 75% and enantiomeric ratios of up to 1:99.