Abstract Several nucleophiles were separately treated with methyl and phenyl 2,3-anhydro-4,6- O -benzylidene-3-deoxy-3-nitro-β- d -allopyranoside, to give 2-substituted aldos-3-ulose derivatives. In the latter case, the subsequent β-elimination of the aglyconic phenyl group always occurred to afford the corresponding glycal. Reaction mechanisms thereof are also discussed.