A concise synthesis of the O-glycosylated amino acid building block; using phenyl selenoglycoside as a glycosyl donor

A new glycosylation methodology for synthesizing a protected Tf antigen is described. The key step is to use phenyl selenoglycoside as a glycosyl donor, thereby successfully establishing O-linked Fmoc-protected threoninyl monosaccharide in an excellent yield with high α selectivity. From protected d-galactal, a protected Tf antigen building block is obtained in 40% total yield.