Novel cyclohexyl-based aminophosphine ligands and use of their Ru(II) complexes in transfer hydrogenation of ketones

Two new aminophosphines - furfuryl-(N-dicyclohexylphosphino)amine, [Cy2PNHCH2-C4H3O] (1) and thiophene-(N-dicyclohexylphosphino)amine, [Cy2PNHCH2-C4H3S] (2) - were prepared by the reaction of chlorodicyclohexylphosphine with furfurylamine and thiophene-2-methylamine. Reaction of the aminophosphines with [Ru((6)-p-cymene)(-Cl)Cl](2) or [Ru((6)-benzene)(-Cl)Cl](2) gave corresponding complexes [Ru(Cy2PNHCH2-C4H3O)((6)-p-cymene)Cl-2] (1a), [Ru(Cy2PNHCH2-C4H3O)((6)-benzene)Cl-2] (1b), [Ru(Cy2PNHCH2-C4H3S)((6)-p-cymene)Cl-2] (2a) and [Ru(Cy2PNHCH2-C4H3S)((6)-benzene)Cl-2] (2b), respectively, which are suitable catalyst precursors for the transfer hydrogenation of ketones. In particular, [Ru(Cy2PNHCH2-C4H3S)((6)-benzene)Cl-2] acts as a good catalyst, giving the corresponding alcohols in 98-99% yield in 30min at 82 degrees C (up to time of flight588h(-1)). Copyright (c) 2014 John Wiley & Sons, Ltd.