Acetate Acetylacetonate Ampy Ruthenium(II) Complexes as Efficient Catalysts for Ketone Transfer Hydrogenation
Daniela A. Hey, Michael J. Sauer, Pauline J. Fischer, Eva‐Maria H. J. Esslinger, Fritz E. Kühn, Walter Baratta
Abstract
Abstract The mixed acetate acetylacetonate (acac) ruthenium(II) phosphine complexes Ru(OAc)(acac)P 2 [P 2 =(PPh 3 ) 2 , Ph 2 P(CH 2 ) 4 PPh 2 (dppb)] were prepared by protonation of Ru(OAc) 2 (PPh 3 ) 2 with acetylacetone in dichloromethane. Reaction of the dppb derivative with 2‐(aminomethyl)pyridine (ampy) affords the complex Ru(OAc)(acac)(ampy)(dppb), which converts to [Ru(acac)(ampy)(dppb)](OAc) in toluene at 90 °C. In the former derivative the ampy ligand is monodentate and coordinates through the NH 2 ‐moiety. The isolated acac complexes are active catalysts for the transfer hydrogenation of ketones with loadings as low as 0.01 mol%, the ampy having a strong accelerating effect. Several aromatic and aliphatic ketone substrates are converted to their corresponding alcohols, and different electronic influences through substituents on acetophenone are tolerated.