Novel P 2 N 4 -donors containing chiral 22membered 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 À1 ) and excellent enantioselectivity with up to 99% ee in the asymmetric transfer hydrogenation of various aromatic ketones.

[reaction: see text] Catalytic systems generated in situ from the chiral PNNP ligands with iridium or rhodium hydride complexes exhibited excellent catalytic activity and good enantioselectivity in the asymmetric transfer hydrogenation of aromatic ketones without added base. The best result was obtained in the IrH(CO)(PPh(3))(3)-ligand 2 catalytic system with up to 99% yield and 97% ee.

Chiral diaminodiphosphine-Ir(I) complexes were found to efficiently catalyze enantioselective oxidation of racemic secondary alcohols in acetone. In the presence of base, oxidative kinetic resolution of the alcohols proceeded smoothly with excellent enantioselectivity (up to 98% ee) under mild conditions. [reaction: see text].

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