Mixed organofluorine-organosilicon chemistry Part 12: Reactions of difluoroenoxysilanes with glycosyl donors: Synthesis of difluoro-C-glycosides and difluoro-C-disaccharides

Difluoroenoxysilanes, prepared from acylsilanes and trifluoromethyltrimethy lsilane under fluoride activation, were glycosylated with some glycosyl don ors (acylglycosides. glycals) Lo yield difluoro-C-glycosides with a difluor omethylene group in the place of the anomeric oxygen. This reaction strongl y depends on the substituent in the 2-position of the glycosyl donor. Appli cation of this methodology to a xylose-derived acylsilane led to the format ion of difluoro-C-disaccharides as an isosteric O-glycosyl mimetic.