Highly Enantioselective Transfer Hydrogenation of Ketones with Chiral (NH)2P2 Macrocyclic Iron(II) Complexes

Bis(isonitrile) iron(II) complexes bearing a C-2-symmetric diamino (NH)(2)P-2 macrocyclic ligand efficiently catalyze the hydrogenation of polar bonds of a broad scope of substrates (ketones, enones, and imines) in high yield (up to 99.5%), excellent enantioselectivity (up to 99% ee), and with low catalyst loading (generally 0.1 mol%). The catalyst can be easily tuned by modifying the substituents of the isonitrile ligand.