Asymmetric transfer hydrogenation of aryl ketones catalyzed by salt-free two samarium centers supported by a chiral multidentate alkoxy ligand

reaction: see text] We synthesized a chiral multidentate ligand, (R,R,R,R)-N,N,N',N'-tetra(2-hydroxy-2-phenylethyl)-1,3-xylylene diamine (R)-2], which can support two metals at adjacent positions. Asymmetric transfer hydrogenation of acetophenone and its derivatives was conducted by using salt-free bimetallic lanthanoid complexes of (R)-2, and the combination of two samarium atoms and (R)-2 was found to be the best catalyst system for asymmetric transfer hydrogenation of aryl ketones in high enantioselectivity (up to >99% ee).