Air-Stable Catalysts for Highly Efficient and Enantioselective Hydrogenation of Aromatic Ketones

A series of chiral trans-[RuCl2(dipyridylphosphine)(1,2-diamine)] complexes have been synthesized and characterized by NMR and single-crystal X-ray diffraction studies. These Ru complexes combined with (CH3)3COK in 2-propanol formed a very effective catalyst system for the hydrogenation of a diverse range of simple aromatic ketones with high activity (substrate-to-catalyst ratio up to 100 000) and excellent enantioselectivity (up to >99.9%). The catalyst system was also found to be stable in solution even under a normal atmosphere.