A CONVENIENT STRATEGY FOR REPLACEMENT OF THE ANOMERIC HYDROXYL GROUP BY DIFLUOROMETHYL FUNCTIONALITY IN CARBOHYDRATE-DERIVATIVES

A series of carbohydrate gem-difluoroenol ethers are readily prepared by the reaction of the corresponding lactones with dibromodifluoromethane, tris(dimethylamino)phosphine and zinc. Subsequent catalytic hydrogenation provides difluoromethyl C-glycoside analogues in which the exocyclic oxygen atom has been replaced by a difluoromethylene unit.