P-Stereogenic monophosphines with the 2-p-terphenylyl and 1-pyrenyl substituents. Application to Pd and Ru asymmetric catalysis
tThe synthesis of five optically pure P-stereogenic monophosphines of the type PPhArR (Ar = 2-p-terphenylyl (a), 1-pyrenyl (b); R = OMe, Me, i-Pr) is described. The ligands were fully characterisedand the absolute configurations of PPh(1-pyrenyl)R (3b and 5b; R = OMe and Me respectively) wereconfirm...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repositorio: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:recercat.cat:2445/165417 |
| Acceso en línea: | https://hdl.handle.net/2445/165417 |
| Access Level: | acceso abierto |
| Palabra clave: | Catàlisi asimètrica Lligands Pal·ladi (Element químic) Ruteni Enantioselective catalysis Ligands Palladium Ruthenium |
| Sumario: | tThe synthesis of five optically pure P-stereogenic monophosphines of the type PPhArR (Ar = 2-p-terphenylyl (a), 1-pyrenyl (b); R = OMe, Me, i-Pr) is described. The ligands were fully characterisedand the absolute configurations of PPh(1-pyrenyl)R (3b and 5b; R = OMe and Me respectively) wereconfirmed by X-ray diffraction. The complexation of the monophosphines to Pd and Ru organometal-lic units yielded the neutral complexes [PdCl( 3-2-Me-allyl)P] (10-12) and [RuCl2( 6-p-cymene)P](16-18). Complete characterisation, including the crystal structure determination of [RuCl2( 6-p-cymene)(PMePh(2-p-terphenyl))] (17a) is provided. Neutral palladium complexes appeared as mixturesof two diastereomers in solution according to NMR. The synthesis and characterisation of four cationic[Pd( 3-2-Me-allyl)(P)2]PF6(13 and 14) is also described. The application of neutral Pd complexes tocatalytic styrene hydrovinylation afforded moderate conversions, high chemoselectivities (>92%) to 3-phenyl-1-butene and up to 43% ee with precursor 12a. Cationic Pd complexes were tested as catalyticprecursors in allylic substitution of rac-3-acetoxy-1,3-diphenyl-1-propene (rac-I), with the anion ofdimethylmalonate and benzylamine as nucleophiles, obtaining full conversions and up to 80% ee in alkyl-ation and 60% ee in amination with precursor 13a. Finally, ruthenium complexes were used as catalyticprecursors in transfer hydrogenation of acetophenone, with complete conversions after several hoursbut low enantioselectivities. |
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