Ring-fused gem-dibromocyclopropanes as precursors to enantiomerically pure D- and L-series 3-deoxy- and 2-amino-2,3-dideoxyaldohexose derivatives

The gem-dibromocyclopropanes that undergo silver(1)-promoted electrocyclic ring-opening and the resulting π-allyl cations trapped with a range of nucleophiles to give mixtures of cyclohexenyl bromides were discussed. It was found that the subjection of these products to ozonolytic cleavage afforded differentially protected and enantiopure D- and L-series 3-deoxy- and 2-amino-2,3-dideoxyaldohexoses. The results showed that monosaccharide derivatives, as well as related compounds were likely to prove useful as 'building blocks' in the construction of a range of carbohydrates.