Iron‐Catalyzed Highly Enantioselective Reduction of Aromatic Ketones with Chiral P 2 N 4 ‐Type Macrocycles

Novel P 2 N 4 ‐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, Fe 3 (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.