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

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 H2 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. Cobalt‐catalyzed enantioselective hydrogenation of ketones: the cobalt‐catalyzed asymmetric hydrogenation of various ketones has been investigated using H2 as a hydrogen source, affording the corresponding chiral alcohols with up to 99 % yield and 95 % ee.