Methylfluorovinylsilanes and stannanes Me4-xM(CF = CF2)x(M = Sn, x = 1
; Si, x = 1,2) can be prepared in good to excellent yields by the reac
tion of CF2 = CFBr with a mixture of the corresponding Me4-xMClx and P
(NR2)3 in polar solvent. Similarly, the novel silane CF3 (SiMe3)C = CF
2 was obtained from CF3CBr = CF2.