Iridium complexes of chiral diamines containing carbon and nitrogen stereocentres: synthesis, structure and evaluation as transfer hydrogenation catalysts

Novel Rh(III) and Ir(III) complexes of a chiral diamine ligand have been synthesised and structurally characterised. Both complexes were formed as a single diastereomeric species with a single configuration at nitrogen. Ir complexes of the chiral diamine were found to be active in the asymmetric transfer hydrogenation of bulky ketones. Excellent conversions (up to 100%) and moderate enantioselectivities (up to 60%) were obtained in the asymmetric reduction of 2,2-dimethylpropiophenone.