Asymmetric transfer hydrogenation of ketones catalyzed by ruthenium(II) complexes bearing a chiral phosphinoferrocenyloxazoline ligand

The catalytic activity in asymmetric transfer hydrogenation of ketones using octahedral and half-sandwich (η5-indenyl and η6-arene) ruthenium(II) complexes containing the chiral ligand (4S)-2-[(Sp)-2-(diphenylphosphino)ferrocenyl]-4-(isopropyl)oxazoline (FcPN) has been explored. Catalytic studies with complex fac-[RuCl2{η2(P,N)-FcPN}(PMe3)2] (1) show excellent TOF values (9600 h−1). Experiments in the presence of free FcPN, which lead to an increase in conversion rates and ee values when the catalyst is complex [Ru(η5-C9H7){κ2(P,N)-FcPN}(PPh3)][PF6] (4) have been carried out. The characterization of the new complexes mer–trans-[RuCl2{P(OMe)3}2{κ2(P,N)-FcPN}] and of the water-soluble complexes fac- and mer–trans-[RuCl2(PTA)2{κ2(P,N)-FcPN}] is also reported.