SYNTHESIS OF A SERIES OF METHYL BETA-GLYCOSIDES OF (1-]6)-BETA-D-GALACTO-OLIGOSACCHARIDES HAVING ONE RESIDUE DEOXYGENATED AT POSITION-3

Methyl β-glycosides of β-(1→6)-linked d-galactobioses (13 and 16) and -galactotrioses (21, 24, and 26) containing a 3-deoxy-β-d-xylo-hexopyranosyl moiety either as one of the end units or the internal unit have been synthesized. The extension of the oligosaccharide chain was achieved, inter alia, by the use of two newly synthesized glycosyl donors derived from 3-deoxy-d-xylo-hexopyranose, namely, 2,4,6-tri-O-benzoyl-3-deoxy-α-d-xylo-hexopyranosyl chloride (8) and 2,4-di-O-benzoyl-6-O-bromoacetyl-3-deoxy-α-d-xylo-hexopyranosyl chloride (10). Glycosylation reactions were mediated by silver triflate under base-deficient conditions. © 1990.