Unambiguous enantiospecific syntheses of 1,5-dideoxy-1,5-imino-D-mannitol (LU1, 1-deoxy-mannojirimycin) are reported (i) from D-mannose via hydrogenation of a 5-azido-5-deoxy mannose, and (ii) from D-glucose, in which the key step involves nucleophilic substitution of a trifluoromethanesulphonyl group from C-2 of D-glucose. © 1984.
