A convenient catalyst system employing RuCl3 or RuBr3 for metathesis of acyclic olefins

A convenient ruthenium catalyst system for olefin metathesis was developed that is effective for metathesis of acyclic olefins.. The catalyst system i s comprised of RuCl3 or RuBr3 hydrate, a phosphine, and an alkyne which are simply combined with the olefin reactant and heated to moderate temperatur es, preferably in the presence of H-2 to obtain highest activity. Catalyst components are readily available and no syntheses of ruthenium complexes ar e required. The sq stem was found to be particularly active and selective f or metathesis of acyclic alpha-olefins. The most effective phosphines ident ified were PCy3, P(i-Pr)(3), PH(t-Bu)(2), and PMe(t-Bu)(2). Of the alkynes tested, 2-butyne-1,4-diol diacetate yielded the most active system for alph a-olefin metathesis, Self-metathesis reactions of 1-octene utilizing PCy3 a nd 2-butyne-1,4-diol diacetate proceeded with initial turnover rates of abo ut 1000 min(-1) and total turnover numbers of 50,000-100,000 after 2 h at 8 0-90 degrees C. The catalyst system was also demonstrated effective for met athesis of methyl oleate. (C) 1999 Elsevier Science B.V. All rights reserve d.