A new strategy for stereoselective synthesis of sialic acid-containing glycopeptide fragment Original Research Article

Sialic acid donor 5, which has a thiophenyl group as a stereocontrolling auxiliary and thiomethyl group as a leaving group was prepared and subjected to model glycosylation. Reactions with acceptor substrates 6, 7, and 8 gave coupled products 9b, 10b, and 11b, respectively, in a higher efficiency than previously observed for the bromide 1a. This reaction was further applied to the synthesis of protected glyco-amino acid fragment 12, that is strategically designed for the synthesis of sialic acid containing glycopeptides.