Fragmentation of carbohydrate anomeric alkoxyl radicals. A new synthesis of chiral ß-iodo azides, vinyl azides and 2H-azirines

The reaction of 3-azido-2,3-dideoxy-hexopyranose compounds from the D-gluco, D-galacto, D-lacto, and L-arabino carbohydrate series, with (diacetoxyiodo)benzene and iodine, generated 2-azido-1,2-dideoxy-1-iodo-alditols with one carbon less than the starting carbohydrate. These -iodo azides could be transformed by dehydroiodination into vinyl azides, which in turn afforded 3-monosubstituted 2H-azirines under thermal conditions. These -iodo azides and 2H-azirines may be interesting chiral synthons for the preparation of more complex heterocyclic systems.