Synthesis of an H type 2 and a Y (Le(y)) glycoside from thioglycoside intermediates.

The trisaccharide 2-(p-trifluoroacetamidophenyl)ethyl 2-acetamido-2- deoxy-4-O-[2-O-(alpha-L-fucopyranosyl)-beta-D-galactopyranosyl]-beta-D- glucopyranoside 1 and the tetrasaccharide 2-(p-trifluoroacetamidophenyl)ethyl 2-acetamido-2-deoxy-3-O-(alpha-L- fucopyranosyl)-4-O-[2-O-(alpha-L-fucopyranosyl)-beta-D-galactopyranosyl]- beta-D-glucopyranoside 2 were synthesized. Thioglycosides, suitably protected, activated directly with methyl trifluoromethanesulfonate or dimethyl(methylthio)sulfonium tetrafluoroborate or activated after bromine treatment with halophilic reagents, were used as glycosyl donors in the construction of the glycosidic linkages.