Iron competes with pricey ruthenium: The first catalyst systems using iron complexes for asymmetric H2 hydrogenation at 50 °C and asymmetric transfer hydrogenation at room temperature has been discovered. The transfer hydrogenation activity is similar to that of the best ruthenium catalyst. Surprisingly, the precatalysts have a tetradentate diiminodiphosphine ligand which has no NH functionality.

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Alcohols Q 0230Highly Efficient Catalyst Systems Using Iron Complexes with a Tetradentate PNNP Ligand for the Asymmetric Hydrogenation of Polar Bonds. -Catalysts (I) are active in the solvent transfer hydrogenation of ketones, aldehydes and imines at room temperature to yield the products with high conversion but moderate enantioselectivities. -(SUI-SENG, C.; FREUTEL, F.; LOUGH, A. J.; MORRIS*, R. H.; Angew. Chem., Int. Ed. 47 (2008) 5, 940-943; Dep. Chem., Univ. Toronto, Toronto, Ont. M5S 3H6, Can.; Eng.) -Y. Steudel 22-074