Syntheses of (3R,4R,5R,6R)-tetrahydroxyazepane (1,6-dideoxy-1,6-imino-d-mannitol) and (3S,4R,5R,6R)-tetrahydroxyazepane (1,6-dideoxy-1,6-imino-d-glucitol)

Syntheses of 1,6-dideoxy-1,6-imino-d-mannitol (d-mannoazepane) () and 1,6-dideoxy-1,6-imino-d-glucitol (d-glucoazepane) () from d-isoascorbic acid and d-glucono-1,5-lactone, respectively, are described. The key step in both routes involved reductive aminative 1,6-cyclization with retention of configurations to give the corresponding lactams, which were subsequently reduced to afford compounds and in 24 and 28.5%, overall yield, respectively.