An improved synthesis of 1-phenylpentafluoropropenes

1-Phenylpentafluoropropene and a number of its para- and ortho-substituted derivatives were prepared in high yields by reaction of hexafluoropropene with etheral solutions of corresponding phenylmagnesium bromides in sealed glass tubes under autogenous pressure. The products were obtained as mixtures of the Z and E isomers, which ratios varied from 1/2 to 1/6 in favour of the E forms. ¹⁹F n.m.r. and i.r. spectra and b.p. of the 1-phenylpentafluoropropenes are reported.