Rhodium complexes containing chiral P-donor ligands as catalysts for asymmetric hydrogenation in non conventional media

• Published in: Catalysis letters Vol. 141; no. 6; pp. 808 - 816
• Main Authors: Escárcega-Bobadilla, Martha V., Rodríguez-Pérez, Laura, Teuma, Emmanuelle, Serp, Philippe, Masdeu-Bultó, Anna M., Gómez, Montserrat
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.06.2011; Springer; Springer Nature B.V
• Subjects: Asymmetry; Carbon; Carbon dioxide; Catalysis; Catalysts; Chemistry; Chemistry and Materials Science; Coordination compounds; Dichloromethane; Enantiomers; Exact sciences and technology; Fluorination; General and physical chemistry; Hydrogenation; Industrial Chemistry/Chemical Engineering; Ionic liquids; Ions; Leaching; Ligands; Liquid phases; Multi wall carbon nanotubes; Nanotubes; Organometallic Chemistry; Physical Chemistry; Recycling; Rhodium; Solvents; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Asymmetric hydrogenation; Chiral monodentate P-donor ligands; Ionic liquids; Rhodium; Supercritical CO; Enantioselectivity; Support; Octane derivatives; Carbon dioxide; Immobilization; Liquid phase; Asymmetric induction; Hydrogenation; Ionic liquid; Molecular species; Recycling; Platinoid; Rhodium complex; Catalytic reaction; Transition metal; Fluorine compound; Supercritical state; Carbon; Organic solvent; Multiwalled nanotube; Catalyst; Monodentate ligand
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-011-0568-4

Rhodium-catalysed asymmetric hydrogenation using P-donor ligands, such as new fluorinated ( R )-BINOL and azadioxaphosphabicyclo[3.3.0]octane derivatives was carried out in different reaction media such as organic solvent (CH 2 Cl 2 ), ionic liquid ([BMI][PF 6 ]), supercritical carbon dioxide (scCO 2 ) and [BMI][PF 6 ]/scCO 2 mixture. The best enantioselectivities were obtained in neat [BMI][PF 6 ], allowing a recycling up to ten times without activity loss. However, the enantioselectivity was lost due to ligand leaching. The ionic liquid phase containing rhodium molecular species was supported on functionalized multi-walled carbon nanotubes in order to improve the recycling, but unfortunately the asymmetric induction was lost upon catalyst immobilization. Graphical Abstract Rh-catalysed asymmetric hydrogenation was carried out in different reaction media (dichloromethane, scCO 2 , [BMI][PF 6 ] and the mixture of scCO 2 /[BMI][PF 6 ]) using chiral P-donor ligands under soft conditions. The best catalytic system was obtained in ionic liquid medium and could be recycled up to ten times without activity loss. The ionic liquid catalytic phase supported on functionalized multi-walled carbon nanotubes did not improve its catalytic behaviour.