METATHESIS OF SILICON-CONTAINING OLEFINS .10. METATHESIS OF VINYLTRIMETHYLSILANE CATALYZED BY RUTHENIUM COMPLEXES

Self metathesis of vinyltrimethylsilane in the presence of an oxygenat ed benzene solution of RuCl2(PPh3), and RuH2(PPh3)4 follows an unusual course and yields two products, 1,2-bis(silyl)ethene (E) and 1,1-bis( silyl)ethene, with products of dimerization, namely 1,4-bis(silyl)bute nes-2 (E + Z) and butenylsilanes as well as hexamethyldisiloxane. Gase ous ethylene and traces of ethane were also detected. It is proposed t hat vinylsilane is inserted into the Ru-Si bond (via ortho-metallation of the ruthenium triphenylphosphine complex) in competition with path ways involving metal-carbene species. Complexes of ruthenium containin g no phenylphosphine give stereoselectively only the (E)-product of me tathesis (even in the absence of oxygen and hydrosilane co-catalysts) accompanied by traces of the same by-products.