Unsymmetrical Ferrocenylethylamine-DerivedMonophosphoramidites: Highly Efficient ChiralLigands for Rh-Catalyzed EnantioselectiveHydrogenation of Enamides and α-DehydroaminoAcid Derivatives
A new family of unsymmetrical ferrocenylethylamine-derived monophosphoramidites were synthesized and successfully applied in the Rh-catalyzed enantioselective hydrogenation of a range of enamides and α-dehydroamino acidesters, and ee values of up to 99.5% were obtained for bothtypes of substrate. These results suggest that unsymmetricalamine-derived monophosphoramidites can also exhibit excellent enantioselectivity for a broad range of substrates,comparable to or higher than those of the most efficientsymmetrical amine-derived monophosphoramidites reportedthus far.