A process for making .beta.-alkenyltrimethylsilanes and trimethylsilyl carboxylates. The process comprises contacting a mixture comprising hexamethyldisilane and an alkene carboxylate having a .beta.-unsaturated carbon atom with novel organo-palladium and organo-nickel complexes, as catalysts, at a temperature within a range of about 100.degree. C. to 250.degree. C. The present process is especially useful for making allyltrimethylsilane and trimethylsilyl acetate.