Synthesis and utility of fluorinated acylsilanes

A variety of fluorinated acylsilanes were synthesized. Difluoroacetyltrialkylsilanes (3) were prepared through retro-Brook rearrangement from reaction of trifluoroethanol and chlorotrialkylsilanes in the presence of LDA. Sequential Mg-promoted defluorination in the presence of chlorotrimethylsilane, followed by acidic hydrolysis resulted in the formation of monofluoroacetyltrialkylsilanes (4). Electrophilic fluorination of 1,1-difluoro-2-trialkylsilyl-2-trialkylsilyloxy ethenes (2) with Selectfluor® gave trifluoro-acetyltrialkyl silanes (5). The synthetic utility of fluorinated acylsilanes in olefination and allylation reactions under a variety of reaction conditions is also described.