Polyfluoroalkyl derivatives of silicon. Part XV. The preparation and pyrolysis of 1-trifuoromethyl-1,2,2-trifluorethyl-, 1-trifluoromethyl-1,2,3,3,3-pentafluropropyl-, 2H-hexflurocyclobutyl-, 3H-pentafluropropyl-, and 1,2,2-trifluoroethyl-trihalogenosilanes

Abstract

The trichloro(polyfluroalkyl)silanes are formed in high yield by the photochemical reaction of trichlorosilance with the appropriate fluoro-olefin and they are readily converted into the trifluorosilyl analoguesby reaction with antimony(III) fluoride. The reaaction of trichlorosilane with hexafluorocyclobutene gives exclusively the trans-adduct. All the trihalogeno(polyfluoroalkyl)silanes an trihalogeno(2H-hexafluorocyclobutyl)silanes except trichloro(3H-pentafluropropyl)silane decompose thermally by β-elimination processes; the latter silane partly decomposes by an α-elimination process via an intermediate carbene and it partly undergoes rearrangement by exchange of fluorine of the α-carbon by chlorine on sillicon.