ChemInform Abstract: Chemistry of a Novel Zerovalent Ruthenium π-Acidic Alkene Complex: Ru(η6-1,3,5-cyclooctatriene) (η2-dimethyl fumarate)2

A novel zerovalent ruthenium complex with a π-acidic ligand, Ru(η6-cyclooctatriene)(η2-dimethyl fumarate)2 (1), was prepared from Ru(η4-cyclooctadiene)(η6-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[6.6.0.02,6.03,13.010,14]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.