6-Amino-2,5-imino-D-glucitol 2 and 6-amino-1,5-imino-D-mannitol 3, substituted by a free hydroxyl group, have been synthesized from the conformationally flexible N-Boc bis-aziridine 1. Regioselective ring-opening of 1 by acetic acid is a straight way towards 2, while reaction of 1 with water or allylic alcohol under ytterbium triflate catalysis produces selectively the azapyranose 3. Nitrous deamination carried out on the cyclic carbamate-protected pyrrolidine 4 leads to a 1:1 mixture of both 2,5-imino-D-glucitols 5 and 6 bearing a free hydroxyl substituent either at C-1 or at C-6.