Synthesis of Polyhydroxylated 2<i>H</i>-Azirines and 2-Halo-2<i>H</i>-azirines from 3-Azido-2,3-dideoxyhexopyranoses by Alkoxyl Radical Fragmentation

The reaction of 3-azido-2,3-dideoxypyranose and 3-azido-2,3-dideoxy-2-halohexopyranose compounds with (diacetoxyiodo)benzene and iodine generated 2-azido-1,2-dideoxy-1-iodoalditols and 2-azido-1,2-dideoxy-1-halo-1-iodoalditols, respectively. These β-iodo azides could be transformed by chemoselective dehydroiodination into 2-azido-1,2-dideoxy-4-O-formyl-pent-1-enitols and (Z,E)-2-azido-1,2-dideoxy-1-halo-4-O-formyl-pent-1-enitols in good yields. Thermolysis and photochemical studies of these vinyl azides and 1-halovinyl azides for the synthesis of polyhydroxylated 3-alkyl-2H-azirines and the hitherto unknown 2-halo-3-alkyl-2H-azirines have also been accomplished.