Synthesis of 6-amino-1,6-anhydro-6-deoxysugar derivatives

Staudinger reaction of triphenylphosphine with 2,3,4-tri-O-acetyl-6-O-p-tolylsulfonyl-β-d-glycopyranosyl azides led to an anomeric iminophosphorane which rearranged in situ by elimination of the sulfonate at C-6. The 1,6-anhydro-6-deoxy-6-triphenylphosphonioamino-β-d-glycopyranose salts thus obtained were transformed into the corresponding 2,3,4-tri-O-acetyl-6-amino-1,6-anhydro-6-deoxy-β-d-glycopyranoses which were further N-acylated or N-alkoxycarbonylated. 1H and 13C NMR of these products show the occurrence of two rotamers in solution, due to restricted rotations around the amide bond.