Synthesis of the methyl alpha-glycosides of some isomalto-oligosaccharides specifically deoxygenated at position C-3.

Methyl alpha-isomaltoside and methyl alpha-isomaltotrioside specifically deoxygenated at position C-3 of various glucopyranosyl units were synthesized by condensation of either 1,6-di-O-acetyl-2,4-di-O-benzyl-3-deoxy-alpha,beta-D-ribo-hexopyranos e (7) or 1,6-di-O-acetyl-2,3,4-tri-O-benzyl-alpha,beta-D-glucopyranose [mediated by silver perchlorate and tin(IV) chloride] with suitably blocked derivatives of methyl alpha-D-glucopyranoside, its 3-deoxy analog (6), or methyl 3'-deoxy alpha-isomaltoside (10), respectively.