A Photoinduced, Nickel‐Catalyzed Reaction for the Stereoselective Assembly of C‐ Linked Glycosides and Glycopeptides

C -Alkyl glycosides and glycoproteins exist in natural products, and are prized for their role as carbohydrate mimics in drug design. However, a practical strategy that merges glycosyl donors with readily accessible reagents, derived from abundant carboxylic acid and amine feedstocks, is yet to be conceived. Here, we show that a nickel catalyst promotes C-C coupling between glycosyl halides and aliphatic acids or primary amines (converted to redox-active electrophiles in one step), in the presence of Hantzsch ester and LiI (or Et 3 N) under blue LED illumination to deliver C -alkyl glycosides in high diastereoselectivities. Mechanistic studies support the photoinduced formation of alkyl radicals that react with an in situ -generated glycosyl-nickel species to facilitate cross-coupling. Through this manifold, innate CO 2 H and NH 2 motifs embedded within amino acids and oligopeptides are selectively capped and functionalized to afford glycopeptide conjugates via late-stage glycosylation.