Asymmetric Hydrophosphonylation of α,β-Unsaturated Ketones Catalyzed by Rare-Earth Metal Complexes Bearing Trost Ligands.

Chiral dinuclear rare-earth metal complexes RE 2 L n 2 ( n = 1, RE = Y( 1 ), Eu( 2 ), Nd( 3 ), La( 4 ), Gd( 5 ); n = 2, RE = Eu( 6 ), Gd( 7 )) stabilized by the corresponding Trost ligands H 3 L 1 or H 3 L 2 (H 3 L 1 = ( S , S )-2,6-bis[2-(hydroxydiphenylmethyl)pyrrolidin-1-ylmethyl]-4-methylphenol, H 3 L 2 = ( S , S )-2,6-bis[2-(hydroxydiphenylmethyl)pyrrolidin-1-ylmethyl]-4-chlorophenol) were prepared and three unknown complexes 5 - 7 were characterized by X-ray diffraction analysis. The chiral rare-earth metal complexes 1 - 7 displayed high reactivity in the asymmetric hydrophosphonylation of α,β-unsaturated ketones, and 5 mol % of complex 7 together with 10 mol % of chiral diamine (1 S ,2 S )-1,2-cyclohexanediamine were proved to be the optimal catalyst combination. Various hydrophosphonylation products with excellent yields and high to excellent enantiomeric excess (ee) values were obtained in toluene (up to 99% yield, >99% ee).