Synthesis of (R)-2,3-epoxypropyl(1→3)-β-d-pentaglucoside Original Research Article

The title pentasaccharide was synthesized via a 2 + 3 strategy. The disaccharide donor, 3-O-acetyl-2-O-benzoyl-4,6-O-benzylidene-β-d-glucopyranosyl-(1→3)-2-O-benzoyl-4,6-O-benzylidene-α-d-glucopyranosyl trichloroacetimidate (8), was obtained by selective coupling of allyl 2-O-benzoyl-4,6-O-benzylidene-α-d-glucopyranoside with 3-O-acetyl-2-O-benzoyl-4,6-O-benzylidene-α-d-glucopyranosyl trichloroacetimidate (4), followed by deallylation, and trichloroacetimidation. Meanwhile, the trisaccharide acceptor, allyl 2-O-benzoyl-4,6-O-benzylidene-β-d-glucopyranosyl-(1→3)-2-O-benzoyl-4,6-O-benzylidene-β-d-glucopyranosyl-(1→3)-2-O-benzoyl-4,6-O-benzylidene-β-d-glucopyranoside (12), was prepared by coupling of allyl 2-O-benzoyl-4,6-O-benzylidene-β-d-glucopyranosyl-(1→3)-2-O-benzoyl-4,6-O-benzylidene-β-d-glucopyranoside with 4, followed by deacetylation. Condensation of 8 with 12, followed by epoxidation, and deprotection, gave the target pentaoside.