Regiochemistry of epoxide ring opening in methyl 2,3-anhydro-4-azido-4-deoxy-α- and β-l-lyxopyranosides

Methyl 2,3-anhydro-4-O-methanesulfonyl-α-d-ribopyranoside (12) was prepared through a new six-step sequence starting from d-arabinose. Chemical behaviour of 12 was further studied under solvolytic conditions and in the presence of azide anion as a nucleophile. Factors governing the regiochemistry of epoxide ring opening are briefly discussed.