Asymmetric catalysis. 155 - (Cymene)ruthenium halfsandwich complexes with pyrroleoxazoline ligands - Synthesis, stereochemistry, catalysis

Brunner, Henri and Henning, Frauke and Zabel, Manfred (2004) Asymmetric catalysis. 155 - (Cymene)ruthenium halfsandwich complexes with pyrroleoxazoline ligands - Synthesis, stereochemistry, catalysis. ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE, 630 (1). pp. 91-96. ISSN 0044-2313, 1521-3749

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Abstract

The (cymene)ruthenium halfsandwich complexes K1 and K2 with chiral pyrroleoxazoline ligands were synthesized and characterized. The complexes form diastereomers, which only differ in the metal configuration. Complex K1 crystallized as the pure diastereomer S-Ru,S-C4.P-C5. In solution epimerization S-Ru,S-C4,R-C5 reversible arrow R-Ru,S-C4,P-C5 occurred via change of the configuration at the ruthenium atom. The half-life for the first-order reaction at 0.4 degreesC in CD2Cl2 was 50.6 min. Thus, the two diastereomers equilibrate at room temperature. The equilibrium mixtures of K1 and K2 were used as catalysts for the transfer hydrogenation of acetophenone and for the Diels-Alder reaction of cyclopentadiene with methacrolein. Enantiomeric excesses of up to 60% ee were achieved.

Item Type: Article
Uncontrolled Keywords: TRANSITION-METAL-COMPLEXES; ENANTIOSELECTIVE CATALYSIS; TRANSFER HYDROGENATION; CRYSTAL-STRUCTURES; CONFIGURATION; ATOM; halfsandwich complexes; ruthenium; chirality; metal configuration; catalysis; enantioselectivity
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: 27 Jul 2021 09:10
Last Modified: 27 Jul 2021 09:10
URI: https://pred.uni-regensburg.de/id/eprint/38291

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