Silyloxy-rhodium(I) complex catalyzed disproportionation of vinylsilanes and vinylsiloxanes

Effective disproportionation of vinyltrisubstituted silanes and vinyltris(methyl, trimethylsiloxy)silanes as well as intermolecular condensation of divinyltetramethyldisiloxane proceed in the presence of [{(cod)Rh(mu-OSiMe2)}(2)] (I) to yield 1,2-bis(silyl)ethenes accompanied by 1,1-bis(silyl)ethenes as well as cyclic and linear bis(siloxy)ethenes, respectively. The silyloxy-rhodium(I) complex (1) shows much higher catalytic activity than the respective chloro-rhodium(I) complex [{(cod)Rh(mu-Cl-2)}(2)] (II). Mechanistic implications based on catalytic data and very recent evidence reported by Brookhart on hydrovinylation of Rh complex by vinyltrimethylsilane enabled us to suggest the involvement of Rh-H and Rh-Si intermediates as responsible for the catalytic reactions. (C) 2000 Elsevier Science B.V. All rights reserved.