Formation of Organosilicon Compounds. LVIII. Synthesis of a Carbosilane with Propellane Structure 1 (· ? C resp. CH2; x ? Si(CH3)2 resp. Si) is formed by a coupling reaction of BrSi(CH2? Sime2? CH2? Sime2Br)3 2 with CCl4 and Li. The reaction of C6H5me2Si? CH2Li with Clme2Si? CH2Br leads to C6H5me2Si? CH2? Sime2? CH2Br. Metallation with lithium and succeeding reaction with Cl3SiC6H5 produces compound C6H5Si(CH2? Sime2? CH2? Sime2C6H5)3, which than forms 2 by cleavage with bromine.