Solid‐Phase Synthesis of Sialylglycopeptides through Selective Esterification of the Sialic Acid Residues of an Asn‐Linked Complex‐Type Sialyloligosaccharide

Egg yolk provided the starting disialylundecasaccharide for a highly efficient chemoenzymatic synthesis of a biantennary complex-type glycopeptide (see picture). Repetitive protection and deprotection steps required in oligosaccharide synthesis were thus avoided, and the desired glycopeptide was rapidly assembled on a solid phase (R=peptide).