Synthesis of 3-substituted xylopyranosides from 2,3-anhydropentosides

The facile regio- and stereoselective epoxide ring-opening of anhydropentosides described herein provides an attractive pathway to 3-substituted analogs of pentosides. Benzyl 2,3-anhydro-β-D-ribopyranoside (2) and benzyl 2,3-anhydro-β-L-ribopyranoside (7) were obtained from benzyl β-D-arabinopyranoside (1) and benzyl β-L-arabinopyranoside (3) respectively. The anhydropentosides were converted to the corresponding new 3-aminoderivatives (8, 9, 10, and 11), alkoxy derivatives (12, 13, and 14), and deoxy sugar (15) in high yield. Every conversion was a one-step reaction of the anhydroglycoside with the appropriate nucleophile. Side-products due to epoxide migration were not observed.