Mixed organofluorine-organosilicon chemistry. 8. One-pot synthesis of 2,2-difluoro-1,5 diketones from acylsilanes, trifluoromethyltrimethylsilane and enones, and their annulation reaction
摘要:
We describe the synthesis of 2,2-difluoro-1,5-diketones in a one-pot procedure from an acylsilane and trifluoromethyltrimethylsilane, via reaction of difluoroenoxysilanes and enones under electrophilic activation. These diketones are interesting building blocks for the synthesis of gem-difluoro enones or substituted fluorophenols, depending on the annulation conditions. The annulation proceeds with complete regioselectivity controlled by the fluorine substitution. (C) 1998 Elsevier Science Ltd. All rights reserved.
Convergent synthesis of fluoro and gem-difluoro compounds using trifluoromethyltrimethylsilane
摘要:
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-pot methodology. This paper describes reactions with Michael accepters, prenyl, benzyl and glycosyl donors leading to 2,2-difluoro-1,5-diketones, 4,4- or 6,6-difluorocyclohexenones, o- or p-fluorophenols, difluoro analogues of terpenes, and difluoro-C-glycosides. (C) 2000 Elsevier Science S.A. All rights reserved.