A novel zerovalent ruthenium complex with a π-acidic ligand, Ru(η
6-cyclooctatriene)(η
2-dimethyl fumarate)
2 (
1), was prepared from Ru(η
4-cyclooctadiene)(η
6-cyclooctatriene) [Ru(cod)(cot)]. Complex
1 or Ru(cod)(cot) catalyzes various new carbon-carbon bond-forming reactions that include the [2 + 2] cycloaddition of alkenes and alkynes via ruthenacycles, the creation of a new hydrocarbon, pentacyclo[6.6.0.0
2,6.0
3,13.0
10,14]tetradeca-4,11-diene [PCTD], by dimerization of 2,5-norbornadiene via C-C bond cleavage, and the codimerization of alkynes and/or alkenes. Complex
1 was shown to be an excellent mother complex for various zerovalent ruthenium complexes. Complex
1 reacts with amines, phosphines or water to give new zerovalent ruthenium complexes with the ligands. The resulting aqua complexes have a water ligand with an oxygen atom that is a chiral center, i.e., ruthenium complexes with a `chiral water' ligand were prepared and fully characterized.
(Communicated by Hitosi NOZAKI, M.J.A.)
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