A Novel Class of Ferrocenyl‐Aryl‐Based Diphosphine Ligands for Rh‐ and Ru‐Catalysed Enantioselective Hydrogenation

Abstract A series of diphosphines of the novel Walphos ligand family all based on a phenylferrocenylethyl backbone were synthesised in a four‐step sequence. In the rhodium‐ or ruthenium‐catalysed asymmetric hydrogenation of olefins and ketones enantioselectivities of up to 95% and 97%, respectively, were obtained. A 2‐isopropylcinnamic acid derivative of industrial interest was hydrogenated in 95% ee and with turnover numbers of >5000.