Synthesis, Crystal Structure, and Conformation of Methyl 5-Oacetyl-5-cyano-6-deoxy-2,3-O-isopropylidene-β-L-gulofuranoside

Methyl 5-O-acetyl-5-cyano-6-deoxy-2,3-O-isopropylidene-β-L-gulofuranoside was prepared in high yield from methyl 6-deoxy-2,3-O-isopropylidene-α-D-lyxopentodialdo-1,4-furanoside. The configuration at the C5 atom was unambiguosly established by single crystal X-ray analysis of the corresponding 5-O-acetyl derivative. The conformation of the furanose and 1,3-dioxolane rings is also discussed.