Convergent synthesis of fluoro and gem-difluoro compounds using trifluoromethyltrimethylsilane

Trifluorotrimethylsilane reacts with acylsilanes to give the corresponding difluoroenoxysilanes via the Brook rearrangement of the alcoholate adducts. The difluoroenoxysilane reacts in situ with various types of electrophilic substrates, leading to gem-difluoro functionalized derivatives in a one-po t methodology. This paper describes reactions with Michael accepters, preny l, benzyl and glycosyl donors leading to 2,2-difluoro-1,5-diketones, 4,4- o r 6,6-difluorocyclohexenones, o- or p-fluorophenols, difluoro analogues of terpenes, and difluoro-C-glycosides. (C) 2000 Elsevier Science S.A. All rig hts reserved.