Synthesis of the Non-Reducing Hexasaccharide Fragment of Saccharomicin B

DOI: 10.1021/acs.orglett.8b03333

Abstract

A synthesis of the nonreducing end hexasaccharide of saccharomicin B, α-l-Eva-(1→4)-α-l-Eva-(1→4)-α-l-Dig-(1→4)-α-l-Eva-(1→4)-α-l-Dig-(1→4)-β-d-Fuc, has been developed. Selective glycosylations of l-digitoxose (l-Dig) using AgPF₆/TTBP-mediated thioether activation and l-4-epi-vancosamine (l-Eva) using Tf₂O/DTBMP-mediated sulfoxide activation produced the hexasaccharide as a single diastereomer in very good yield. This hexasaccharide is properly functionalized to serve as a glycosyl donor for the total synthesis of saccharomicin B.