A Versatile and High-Yield Route to Active and Well-Defined Catalysts [Ru(bisphosphane)(H)(solvent)3 ](BF4 ).

Simple and efficient: Protonation of [Ru(1,2:5,6-η-cod)(η6 -cot)] (cod=1,5-cyclooctadiene, cot=1,3,5-cyclooctatriene) with HBF4 ⋅Et2 O and then reaction with chiral bisphosphane ligands ($_{\rm PP}^{\frown }$=Me-DuPHOS, BINAP, Tol-BINAP, JOSIPHOS) affords the corresponding [Ru($_{\rm PP}^{\frown }$)(H)(η6 -cot)]+ or [Ru($_{\rm PP}^{\frown }$)(1,2,3,4,5-η-C8 H11 ')]+ (C8 H11 '=2,4-cyclooctadienyl; see scheme). Exposure of these cations to H2 in solvents (sol) such as acetone, methanol, and THF affords [Ru($_{\rm PP}^{\frown }$)(H)(sol)3 ]+ , which are catalysts for (amongst other things) enantioselective hydrogenations of alkenes.