Synthesis of N-Glycopeptides by Convergent Assembly

Electron-donating O -benzylated glycosylamine mono-, di- and trisaccharide representing the reducing terminal of the core structure of N -glycans were incorporated, in anomerically pure from into Leu–Lys–Asn–Gly-Gly–Pro hexapeptide that is a partial structure of the Trp-cage mini-protein by convergent assembly. According to our results acylation of electron-donating O -benzylated glycosylamine with peptide acid under the proposed new reaction conditions led to the formation of glycopeptide in good yield and in anomerically pure form for the first time. This convergent approach allows the synthesis of a series of glycopeptides containing different oligosaccharides without the need to resynthesize the peptide for each individual case.