Institut de Chimie Moléculaire et des Matériaux d'Orsay

Laboratoire de Catalyse Moléculaire - LCM

Asymmetric Homogeneous and Heterogeneous Catalysis

Coordinator: Emmanuelle Schulz (DR CNRS)

Recycling of Chiral Organometallic Catalysts by Electropolymerisation

Mohamed Mellah (Associate Professor), Emmanuelle Schulz (CNRS Research Fellow), Xiang Hong (PhD student), Farah Ibrahim (PhD student)

Objectives : Electropolymerization of functionalized salen derivatives lead to the preparation of new insoluble polymeric chiral complexes. They are used in asymmetric heterogeneous catalysis to promote various catalytic transformations, and they are recovered by simple filtration. We are optimizing their use as homogeneous supported catalysts but also for fixed bed catalysis, to match, at best, the principles of green chemistry.
Recent results : Chromium-salen polymeric complexes have been prepared and successfully used as recyclable catalysts in hetero Diels-Alder and Henry reactions, but also for the ring opening of meso epoxides. Analogous cobalt complexes are stable insoluble catalysts for the hydrolytic kinetic resolution of terminal epoxides. By simple condensation reactions, macrocyclic salen derivatives were also obtained that were used in those catalytic transformations for which a bimetallic activation is necessary for ensuring high activities and selectivities.


See :
“Recoverable chiral salen complexes for asymmetric catalysis : recent progress” - A. Zulauf, M. Mellah, X. Hong, E. Schulz, Dalton Trans. 2010, 39, 6911-6935.
“New chiral calixsalen chromium complexes, recyclable asymmetric catalysts” - A. Zulauf, M. Mellah, E. Schulz, Chem. Eur. J. 2010, 16, 11108-11114.
“Electropolymerization of Chiral Chromium Salen Complexes: New Materials for Heterogeneous Asymmetric Catalysis” - A. Zulauf, X. Hong,F. Brisset,E. Schulz, M. Mellah, New J. Chem. 2012, 36, 1399-1407.
“Electrogenerated polymers as efficient and robust heterogeneous catalysts for the hydrolytic kinetic resolution of terminal epoxides” - X. Hong, M. Mellah, F. Bordier, R. Guillot, E. Schulz, ChemCatChem. 2012, DOI : 10.1002/cctc.201200085

Keywords: asymmetric catalysis, electrosynthesis, polymerization, chiral salen complexes, C-C, C-N and C-O bonds formation, heterogeneous catalysis

Recycling of Chiral Organometallic Complexes by Charge-transfer Complex Formation

Emmanuelle Schulz (CNRS Research Fellow), Dorian Didier (PhD student)

Objectives : fine tuning of new recycling methodologies for chiral organometallic catalysts based on non covalent interactions for :

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    • The enhancement of the catalytic activity
    • The recovery of chiral catalysts
    • The homogeneous supported asymmetric catalysis
    • The fixed-bed heterogeneous asymmetric catalysis
    • The economic and environmentally friendly preparation of valuable functionalized synthons.

    Recent results : Reuse of bis(oxazoline) copper catalysts by charge transfer complex formation. Tests to promote Diels-Alder, Henry cyclopropanation and ene reactions. Recycling methodology in which the same catalyst batch is used to promote different asymmetric catalytic transformations. Heterogeneous catalysis on modified polystyrene resin or on silica.

     


     

    See :
    “Reusable chiral bis(oxazoline)-copper complexes immobilized by donor-acceptor interactions on insoluble organic supports” - G. Chollet, D. Didier, E. Schulz, Catal. Commun. 2010, 11, 351-355.
    “Charge-transfer interactions : an efficient tool for recycling bis(oxazoline)-copper complexes in asymmetric Henry reactions” - D. Didier, C. Magnier-Bouvier, E. Schulz, Adv. Synth. Catal. 2011, 353, 1087-1095.
    “Recycling chiral copper-bis(oxazoline) complexes in an original multi-reactions procedure” - D. Didier, E. Schulz,ChemCatChem. 2011, 3, 1880-1884.
    “A reusable TNF-tagged chiral bis(oxazoline)-copper catalyst for Diels-Alder transformations” - D. Didier, E. Schulz, Synlett 2012, 23, 1309-1314.

  • Keywords: asymmetric organometallic catalysis, recycling by precipitation, heterogeneous catalysis, C-C bond formation, bis(oxazoline) ligands