Addition of methyl 4,6-O-benzylidene-2-deoxy-α-D-erythro-hexopyranosid-3-ulose (1) to acetonitrile in liquid ammonia at −50 to −60° in the presence of lithium amide gave, in high yield, crystalline methyl 4,6-O-benzylidene-3-C-cyanomethyl-2-deoxy-α-D-arabino-hexopyranoside (2) exclusively. The proof of structure2is described. Debenzylidenation of2afforded the branched-chain cyano glycoside3. Compound3was converted into its 3,4,6-tri-O-acetate (8) and 4,6-di-O-p-nitrobenzoate (9) derivatives. Catalytic hydrogenation of3over rhodium on alumina yielded methyl 3-C-2′-aminoethyl-2-deoxy-α-D-arabino-hexopyranoside which was characterized as itsN-2,4-dinitrophenyl derivative (7).