The generation of gem-difluoroallyllithium by the transmetalation reaction

3,3-Difluoroallyltrimethyltin was prepared by reaction of chlorodifluoromethane with the ylide reagent Ph₃PCHCH₂SnMe₃$\text{gem}$-Difluoroallyllithium, which was generated by the reaction of $\text{n}$-butyllithium with 3,3-difluoroallyltrimethyltin in THF at ?95°, was of very limited stability at that temperature. However, $\text{in}$$\text{situ}$ procedures and alternate incremental addition procedures allowed its application in the synthesis of 1,1-difluoroallylsilanes from chlorosilanes and of CH₂CHCF₂C(OH)-Et₂ from 3-pentanone.