trifluoromethyltrimethylsilane under fluoride activation, were glycosylated with some glycosyldonors (acylglycosides, glycals) to yield difluoro-C-glycosides with a difluoromethylene group in the place of the anomeric oxygen. This reaction strongly depends on the substituent in the 2-position of the glycosyldonor. Application of this methodology to a xylose-derived acylsilane led to the formation
Difluorenoxysilanes are produced in high yield by catalytic fluoride activation of a mixture of TFMTMS and an acylsilane: Tetrabutylammonium difluorotriphenylstannate is an excellent catalyst whereas tetrabutylammonium fluoride leads directly to the aldol product corresponding to the difluoromethyl ketone. Some one-pot applications illustrate the usefulness of this methodology.
2,2-Difluoroenol silyl ethers (5) were prepared by electroreductive defluorimation of trifluoromethyl ketones (4) in the presence of chlorotrialkylsilanes (TMSCl, TESCl, TBDMSCl).
We describe the synthesis of new gem-difluoro-C-silylated aldols from acylsilanes and trifluoromethyltrimethylsilane via an aldol reaction. Their defluorosilylation gives aliphatic and alicyclic 2-fluoro-1,3-diketones. The overall reaction sequence can be considered as a new complementary method giving access to a wide variety of such fluorinated 1,3-diketones.