Enantioselective Hydrogenation of Ketones Catalyzed by Chiral Cobalt Complexes Containing PNNP Ligand

Abstract Novel chiral cobalt complexes containing a PNNP‐type ligand were synthesized using a straightforward method. The structures of the cobalt complexes have been fully characterized by X‐ray crystallography, high resolution mass spectrometry (HRMS), and electron paramagnetic resonance (EPR). Using H 2 as the hydrogen source, the cobalt‐catalyzed asymmetric hydrogenation of various ketones was investigated, and the corresponding chiral alcohols were afforded with up to 99 % yield and 95 % ee . To the best of our knowledge, this is the first example of a cobalt‐catalyzed enantioselective hydrogenation of ketones with molecular hydrogen.