Iron-Catalyzed Highly Enantioselective Reduction of Aromatic Ketones with Chiral P2N4-Type Macrocycles

Novel P2N4-donors containing chiral 22-membered macrocyclic ligands have been synthesized and the structures have been determined by an X-ray diffraction study. The catalytic systems in situ generated from triiron dodecarbonyl, Fe3(CO)12, and the chiral macrocyclic ligand exhibited high activity (TOF up to 1940 h-1) and excellent enantioselectivity with up to 99% ee in the asymmetric transfer hydrogenation of various aromatic ketones.