title: Asymmetric Rh-catalyzed hydrogenation using a furanoside phosphite-phosphoroamidite and diphosphoroamidite ligand library.
abstract: A furanoside phosphite-phosphoroamidite and diphosphoroamidite ligand library L1-L5a-f was tested in the asymmetric Rh-catalyzed hydrogenation of α,β-unsaturated carboxylic acid derivatives and enamides. Enantioselectivity depended strongly on the ligand parameters. High enantioselectivities were obtained in the reduction of dimethyl itaconate (up to >99% ee), α-dehydroamino acid esters (up to 99% ee) and several enamides (up to 92% ee). Kinetic and NMR studies on the intermediates of the catalytic cycle of the reaction indicate that the [Rh(P(1)-P(2))(substrate)](+) species is the resting state of the reaction and that the rate dependence is first order in rhodium and hydrogen pressure and zeroth order in the substrate.
authors.affiliation: Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Coll
authors.forename: Oscar
authors.initials: O
authors.lastname: Pàmies
authors.forename: Montserrat
authors.initials: M
authors.lastname: Diéguez