Toward the total synthesis of vineomycin B2: application of an efficient glycosylation methodology using 2,3-unsaturated sugars

The application of an efficient glycosylation methodology using 2,3-unsaturated sugars to synthesize critical precursors required for the total synthesis of an antibiotic, vineomycin B2 (1), was demonstrated. The required disaccharide, the acurosyl rhodinose derivative of 1, was prepared by chemoselective glycosylation using a 2,3-saturated glycosyl acetate corresponding to the rhodinose moiety and a 2,3-unsaturated glycosyl acetate corresponding to the acurose portion. Further, the right-hand side chain of 1, consisting of β-oxo-tert-alcohol and rhodinose, was constructed by a powerful glycosylation approach using a 2,3-unsaturated glycosyl acetate in an ionic liquid under reduced pressure.