The reaction of methylchlorodisilanes with gem-polyhalides in the presence of organic bases has been investigated. The compounds CXCl2SiMeCl2 (X = Cl, H, F and SiMeCl2) were obtained in moderate to high yields from Cl2MeSiSiMeCl2 and polyhalomethanes (e.g., CCl4, CHCl3, CFCl3 and CCl3SiMeCl2) with PPh3 or Bu4NCl as catalyst. The reaction of 1,1,2-trichlorotrimethyldisilane with CCl4 afforded a 1 :
2-tetrachloro-1,2-dimethyldisilane reacted smoothly under mild conditions with carbon tetrachloride to produce (trichloromethyl) methyldichlorosilane 1 in good yield. (Trichloromethyl)dimethylchlorosilane was also readily prepared by the triphenylphosphine-promoted transfer of the trichloromethyl group from 1 to dimethyldichlorosilane.