Cyanohydrins from methyl 6-deoxy-2,3-O-isopropylidene-alpha-L-lyxo-hexofuranosid-4-ulose via Bucherer-Bergs and Strecker reactions

The formation of methyl 4-cyano-6-deoxy-2,3-O-isopropylidene-alpha-L-talopyranoside (3), methyl 4-cyano-6-deoxy-2,3-O-isopropylidene-alpha-L-mannopyranoside (4), methyl 4-cyano-6-deoxy-2,3-O-isopropylidene-beta-D-allopyranoside (5), and methyl 4-cyano-6-deoxy-2,3-O-isopropylidene-beta-D-gulopyranoside (7) from methyl 6-deoxy-2,3-O-isopropylidene-alpha-L-lyxo-hexopyranosid-4-ulose (1) under Strecker amino nitrile synthesis and Bucherer-Bergs hydantoin synthesis reaction conditions, respectively, is reported. Their structures were determined on the basis of NMR and mass spectral data. The configurations of free cyanohydrins 3 and 4 and 4-O-acetylated cyanohydrins 6 and 8 (obtained by acetylation of 5 and 7, respectively) were established by single-crystal X-ray analysis. The conformations of the six-membered pyranose ring and five-membered 1,3-dioxolane ring in compounds 3, 4, 6, and 8 are also reported