An Alternate Route to the Active Chiral Hydrogenation Catalysts [Ru(bisphosphine)(H)(solvent)3]+: Synthesis, Characterization, and Catalytic Evaluation

We report an improved synthesis of cis -[Ru(CH 3 CN) 2 ((1−3-η)-C 3 H 5 )((1,2:5,6-η)-C 8 H 12 )]BF 4 and its use in the synthesis of [Ru(bisphosphine)((1−3:5,6-η)-C 8 H 11 )(CH 3 CN)]BF 4 (where bisphosphine = ( R )-BINAP, ( R )-Tol-BINAP). Thermolyses of the complexes [Ru(bisphosphine)((1−3:5,6-η)-C 8 H 11 )(CH 3 CN)]BF 4 afford [Ru(bisphosphine)((1−5-η)-C 8 H 11 )]BF 4, which serve as convenient precatalysts to the active hydrogenation catalysts fac -[Ru(bisphosphine)(H)(sol) 3 ]BF 4 (sol = THF, acetone, i -PrOH). We compare the properties and activities of these catalysts with those of related, established systems.