Visible-Light-Mediated, Chemo- and Stereoselective Radical Process for the Synthesis of C-Glycoamino Acids

An approach for efficient synthesis of C-glycosyl amino acids is described. Different from typical photoredox-catalyzed reactions of imines, the new process follows a pathway in which α-imino esters serve as electrophiles in chemoselective addition reactions with nucleophilic glycosyl radicals. The process is highlighted by the mild nature of the reaction conditions, the highly stereoselectivity attending C–C bond formation, and its applicability to C-glycosylations using both armed and disarmed pentose and hexose derivatives.