Glycosylation with thioglycosides activated by dimethyl(methylthio)sulfonium tetrafluoroborate: synthesis of two trisaccharide glycosides corresponding to the blood group A and B determinants

Abstract

Two trisaccharide glycosides,p-trifluoroacetamidophenylethyl 3-O-(2-acetamido-2-deoxy-α-d-galactopyranosyl)-2-O-(α-l-fucopyranosyl)-β-d-galactopyranoside andp-trifluoroa-cetamidophenylethyl 2-O-(α-l-fucopyranosyl)-3-O-(α-d-galactopyranosyl)-β-d-galactopyranoside, corresponding to the human blood group A and B determinants, were synthesized. A key fucosylgalactosyl disaccharide derivative was glycosylated with galactosaminyl or galactosyl donors, respectively. Dimethyl (thiomethyl)sulfonium tetrafluoroborate was used for thioglycoside activation in coupling reactions.