Brunner, Henri and Henning, Frauke (2004) Enantioselective catalysis. Part 156. Ruthenium procatalysts and 2-pyridinealdehyde/(S)-NOBIN-derived cocatalysts in the transfer hydrogenation of acetophenone with 2-propanol. MONATSHEFTE FUR CHEMIE, 135 (7). pp. 885-897. ISSN 0026-9247,
Full text not available from this repository. (Request a copy)Abstract
Several ruthenium procatalysts were tested in the transfer hydrogenation of acetophenone with 2-propanol using the chiral imine ligand (S)-2-(2-pyridinylmethylencamino)-2-hydroxy-1,1'-binaphthyl and the corresponding amine (S)-2-(2-pyridinylmethylamino)-2'-hydroxy-1,1'-binaphthyl. Ru(PPh3)(3)Cl-2 was the best procatalyst. Its triphenylphosphane ligands were crucial for the catalytic activity and take part in the chirality transfer. Triphenylphosphane removing reagents such as copper(l) chloride, TEMPO, or TMAO improved the catalytic performance to enantioselectivities up to 99% ee. The findings led to a mechanistic proposal including dissociation equilibria of triphenylphosphane and chelate ring opening of the tridentate chiral binaphthyl ligand. New ligands with an additional chiral center were synthesized and tested as cocatalysts. The nature of catalytically active intermediates was examined by MS and NMR spectroscopy.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ASYMMETRIC TRANSFER HYDROGENATION; ALPHA,BETA-UNSATURATED CARBOXYLIC-ACIDS; LIGAND BIFUNCTIONAL CATALYSIS; DYNAMIC KINETIC RESOLUTION; PONNDORF-VERLEY REDUCTION; AROMATIC KETONES; DENDRITIC CATALYSTS; CARBONYL-COMPOUNDS; PROCHIRAL KETONES; CHIRAL LIGANDS; binaphthyl ligands; ruthenium complexes; chirality; enantioselective catalysis; hydrogen transfer |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie > Alumni or Retired Professors > Prof. Dr. Henri Brunner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 12 Jul 2021 09:04 |
| Last Modified: | 12 Jul 2021 09:04 |
| URI: | https://pred.uni-regensburg.de/id/eprint/37508 |
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