Vinylideneruthenium complexes in catalysis

Vinylidener-uthenium complexes with the general formula [RuCl2(=C=CHR)L-2] (L = PPr3', PCy3, etc.) have been found to serve as good catalyst precursors with high efficiencies for ring-opening metathesis polymerization of cyclic olefins, ring-opening/cross-metathesis between norbomene derivatives and vinyl chalcogenides, ring-closing metathesis of alpha,w-dienes, and (Z)-selective dimerization of terminal alkynes. The complexes are easily prepared in high yields from [RuCl2(p-cymene)](2), L, and RCequivalent toCH, which are all commercially available. Electron-donating substituents (R) at the beta-carbon facilitate the alkyne-vinylidene tautomerization from both kinetic and thermodynamic points of view. (C) 2004 Elsevier B.V. All rights reserved.