Synthesis of All Configurational Isomers of 1,6-Anhydro-2,3,4-trideoxy-2,3-epimino-4-fluoro-β-d-hexopyranoses

We have prepared a full series of 1,6-anhydro-2,3,4-trideoxy-4-fluoro-2,3-epimino-β-d-hexopyranoses. The key step was the reaction of azido sulfonates possessing a free C-4 hydroxyl with DAST and subsequent LiAlH₄ reduction. Nucleophilic displacement of the hydroxyl activated by DAST proceeded without rearrangement and with moderate to good yields. A convenient synthesis of d-mannoepimine from a readily available 3-benzylamino derivative was also developed.