title: Extending the substrate scope of bicyclic p-oxazoline/thiazole ligands for Ir-catalyzed hydrogenation of unfunctionalized olefins by introducing a biaryl phosphoroamidite group.
abstract: This study identifies a series of Ir-bicyclic phosphoroamidite-oxazoline/thiazole catalytic systems that can hydrogenate a wide range of minimally functionalized olefins (including E- and Z-tri- and disubstituted substrates, vinylsilanes, enol phosphinates, tri- and disubstituted alkenylboronic esters, and α,β-unsaturated enones) in high enantioselectivities (ee values up to 99 %) and conversions. The design of the new phosphoroamidite-oxazoline/thiazole ligands derives from a previous successful generation of bicyclic N-phosphane-oxazoline/thiazole ligands, by replacing the N-phosphane group with a π-acceptor biaryl phosphoroamidite moiety. A small but structurally important family of Ir-phosphoroamidite-oxazoline/thiazole precatalysts has thus been synthesized by changing the nature of the N-donor group (either oxazoline or thiazole) and the configuration at the biaryl phosphoroamidite moiety. The substitution of the N-phosphane by a phosphoroamidite group in the bicyclic N-phosphane-oxazoline/thiazole ligands extended the range of olefins that can be successfully hydrogenated.
authors: Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Campus Sescelades, C/Marcel⋅lí Domingo, s/n. 43007 Tarragona (Spain).
authors: Maria
authors: M
authors: Biosca
authors: Alexander
authors: A
authors: Paptchikhine
authors: Oscar
authors: O
authors: Pàmies
authors: Pher G
authors: PG
authors: Andersson
authors: Montserrat
authors: M
authors: Diéguez
keywords: P ligands; asymmetric catalysis; hydrogenation; iridium; ligand design