Silyltriflates are obtained by reaction of the corresponding phenyl derivatives with CF3SO3H. The reaction of silyltriflate with allylmagnesium bromide produced the allylated silane derivatives R2SiHCH2CH=CH2 (R=Me, Ph). They are formed under mild condition with Pt catalysis to polycarbosilane. The cleavage of silicon-phenyl bonds of polysilane by CF3SO3H leads to triflate derivatives of polycarbosilane.