α-D-glucosylation by 6-O-Acetyl-2,3,4-tri-O-benzyl-D-glucopyranose Using Trimethylsilyl Triflate and Pyridine. Synthesis of α-Maltosyl and α-isomaltosyl α-D-Glucosides

Article abstract of DOI:10.1246/bcsj.59.411

The D-glucosylation of methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside and methyl 2,3,6-tri-O-benzyl-β-D-glucupyranoside by 2,3,4,6-tetra-O-benzyl-α-D-glucopyranose using pyridine and excess trimethylsilyl triflate was carried out in dichloromethane, 1,2 dimethoxyethane, and acetonitrile.In a given solvent, the selectivity of the reaction varied depending on the type of hydroxyl group of the glucosyl acceptors.The D-glucosylation of these acceptors with 6-O-acetyl-2,3,4-tri-O-benzyl-D-glucopyranose employing this reagent system in dichloromethane proceeded with good α-selectivity irrespective of the type of the hydroxyl group.This α-D-glucosylation was applied for the synthesis of O-α-D-glucopyranosyl-(1->4)- and -(1->6)-α-D-glucopyranosyl α-D-glucopyranosides from α,α-trehalose.