Synthesis of 2,3-di-O-glycosyl derivatives of methyl α- and β--glucopyranoside

The syntheses are described of 2,3-di-O-glycosyl derivatives of methyl α- and β--glucopyranoside having α--manno-, β--galacto-, α--rhamno-, α--fuco-, and β--fuco-pyranosyl substitutents at O-2 and O-3. The syntheses involved glycoslation of methyl 4,6-O-(benzylidene-α- (24) and β--glucopyranoside (21), and substituted derivatives of 21 bearing 2-O-(2,3,4,6-tetra-O-benzyl-α--mannopyranosyl)-, -(2,3,4,6-tetra-O-acetyl-β--galactopyranosyl)-, -(2,3,4-tri-O-benzyol-α--rhamnopyranosyl)-, and-(2,3,4-tri-O-benzoyl-β--fucopyranosyl) groups.