C-Difluoromethylene-containing, C-trifluoromethyl and C-perfluoroalkyl carbohydrates. Synthesis by carbohydrate transformation or building block methods

The synthetic methods for preparing carbohydrates bearing a C-branched subs tituent of the type CF2-Y, with Y = F, Y = CnF2n+1 or Y = a carbon-attached or heteroatom-attached nonfluorinated residues, are reviewed. Both direct introduction of C-branched fluorinated substituents (direct trifluoromethyl ation, perfluoroalkylation or difluoromethylenation) and building block met hods from fluorinated synthons are considered. (C) 2000 Elsevier Science Lt d. All rights reserved.