Hydrogenation of aromatic ketones catalyzed by (η⁵-C₅(CH₃)₅)Ru complexes bearing primary amines

The rapid hydrogenation of simple aromatic ketones is accomplished by using a combination of (η⁵-C₅(CH₃)₅)Ru complexes and primary amines as a catalyst in 2-propanol. In particular, 1,2-diamines with primary and tertiary amino groups at both ends exhibit a significant ligand acceleration effect. Isotope-labeling experiments using D₂ and 2-propanol-d_n reveal that 2-propanol participates in the activation of H₂ based on a metal/NH bifunctional effect to facilitate the hydrogenation. Asymmetric hydrogenation of prochiral simple ketones with the chiral version of the catalysts provides optically active secondary alcohols with up to 95% ee.