Synthesis and characterisation of new silicon–perfluoropropenyl compounds

Abstract

Novel, stable silicon–pentafluoropropane compounds have been synthesised from the direct reaction of hydrofluorocarbons Z-CFHCFCF₃ (Z-HFC-1225ye) with ⁿBuLi, followed by appropriate silicon-halide. The compounds have been characterized by multinuclear NMR studies (¹⁹F, ¹H, ²⁹Si and ¹³C), DFT studies and structural confirmation was obtained by X-ray diffraction. Based on the outcome of treating synthetic silicon–pentafluoropropene compounds with different nucleophilic sources (ⁿBuLi, ^tBuLi, MeLi, and PhLi) and computed for this reaction DFT energetics, it is clear that the C–F_trans bond is more active than C–F_gem (F_gem and F_trans are labelled with respect to Si). This provides a route for efficient modification of pentafluoropropene group, that can be a crucial step in developing pharmaceuticals that include propenyl or vinyl groups, addressing the demand for medicines based on long carbonic chains.