Cyclic β-iminophosphine: New P-stereogenic ligand for the asymmetric catalysed hydrogenation of ketones

A novel type of asymmetric CO hydrogenation catalysts based on chiral β-iminophosphine rhodium and ruthenium complexes was developed. The chirality of the ligand is centered on the phosphorus atom which can induce moderate enantioselectivity. A synergetic effect on both activity and enantioselectivity is observed when amines are introduced as co-ligands. Acetophenone is thus completely hydrogenated with ee values up to 68%.

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