Photoinduced Copper-Catalyzed Regiodivergent Tertiary Alkylation of α-Imino Carbonyls to Access Sterically Congested α- and β-Amino Acids

We report a photoinduced copper-catalyzed strategy for the substrate-controlled regiodivergent tertiary alkylation of α-imino carbonyls with alkyl bromides under mild conditions. This versatile approach provides direct access to both sterically congested α-monosubstituted α-amino acids and β^2,2,3-amino acids with high regioselectivity, which cannot be accessed by previously developed methods via a single-electron process. Mechanistic studies indicate that the reaction proceeds via two distinct single-electron transfer (SET) pathways involving an azaallyl radical intermediate.