Personne :
Ollevier, Thierry

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Université Laval. Département de chimie
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Voici les éléments 1 - 10 sur 31
  • Publication
    Accès libre
    Bridging lab and industry with flow electrochemistry
    (Cell Press, 2020-10-22) Ollevier, Thierry; Tanbouza, Nour
    A revitalization of organic electrosynthesis has incited the organic chemistry community to adopt electrochemistry as a green and cost-efficient method for activating small molecules to replace highly toxic and expensive redox chemicals. However, many of the critical challenges of batch electrosynthesis, especially for organic synthesis, still remain. The combination of continuous flow technology and electrochemistry is a potent means to enable industry to implement large scale electrosynthesis. Indeed, flow electrosynthesis helps overcome problems that mainly arise from macro batch electro-organic systems, such as mass transfer, ohmic drop, and selectivity, but this is still far from being a flawless and generic applicable process. As a result, a notable increase in research on methodology and hardware sophistication has emerged, and many hitherto uncharted chemistries have been achieved. To better help the commercialization of wide-scale electrification of organic synthesis, we highlight in this perspective the advances made in large-scale flow electrosynthesis and its future trajectory while pointing out the main challenges and key improvements of current methodologies.
  • Publication
    Accès libre
    Hydrogen bond-promoted metal-free hydroamination of alkynes
    (Thieme, 2019-10-07) Bahri, Janet; Ollevier, Thierry; Tanbouza, Nour; Taillefer, Marc; Monnier, Florian
    An original metal-free regio- and stereoselective intermolecular hydroamination of alkynes is described. Various (E)-enamines were obtained from arylacetylenes and aliphatic secondary amines in the presence of ethylene glycol as a solvent. The latter is assumed to play a major role in the mechanism through hydrogen bonding and proton exchange.
  • Publication
    Accès libre
    Synthesis of Imidazolidinone, Imidazolone, and Benzimidazolone Derivatives through Oxidation Using Copper and Air
    (American Chemical Society, 2019-05-06) Ollevier, Thierry; Li, Dazhi
    A new synthetic method of urea derivatives using copper and air was developed. These mild conditions provided moderate to very good yields for 15 examples (53–93%), while low yields were obtained with sterically hindered substrates (3 examples). The reaction was found to go through an in situ-generated copper-N-heterocyclic carbene, which is then oxidized into cyclic urea derivatives possessing alkyl, benzyl, aryl, hydroxy, Boc-protected, and tertiary amine groups
  • Publication
    Accès libre
    Asymmetric Fe II -Catalyzed Thia-Michael addition reaction to α,β-unsaturated Oxazolidin-2-one Derivatives
    (American Chemical Society, 2017-11-20) Ollevier, Thierry; Keipour, Hoda; Gandon, Vincent; Lauzon, Samuel
    A highly enantioselective FeII-catalyzed thia-Michael addition to α,β‑unsaturated carbonyl derivatives was developed. The scope of the reaction was demonstrated with a selection of aromatic, heterocyclic and aliphatic thiols, and various Michael acceptors. The corresponding β-thioethers were obtained in good to excellent yields (up to 98%) and moderate to excellent enantioselectivities (up to 96:4 er). Unusual hepta-coordination of the metal and chelation to α,β-unsaturated oxazolidin-2-one derivatives allowed the construction of a coherent model rationalizing the enantioselective event. DFT calculations support the proposed model for observed stereoselectivities.
  • Publication
    Accès libre
    Iron bis(oxazoline) complexes in asymmetric catalysis
    (Royal Society of Chemistry, 2015-10-23) Ollevier, Thierry
    Asymmetric reactions catalyzed by iron complexes have attracted considerable attention because iron is a ubiquitous, inexpensive, and environmentally benign metal. Various chiral iron complexes can be prepared from bis IJ oxazoline) ligands and be used in asymmetric reactions. This overview charts the development and application of chiral iron bis IJ oxazoline) and pyridine-2,6-bis IJ oxazoline) catalysts through their most prominent and innovative uses in asymmetric catalysis, especially in Lewis acid and oxidation catalysis.
  • Publication
    Accès libre
    CsF/clinoptilolite : an efficient solid base in SNAr and copper-catalyzed Ullmann reactions
    (NRC Research Press, 2015-10-19) Keipour, Hoda; Ollevier, Thierry; Hosseini, Abolfaz; Afsari, Amir; Khalilzadeh, Mohammad A.
    CsF/clinoptilolite was found to be an efficient solid base catalyst for both SNAr and Ullmann ether reactions. A general and efficient one-step procedure was developed for the synthesis of biaryl ethers via direct coupling of electron-deficient aryl halides to phenols using CsF/clinoptilolite. The protocol was also applied to electron-rich aryl halides by addition of a catalytic amount of copper oxide nanoparticles. Both SNAr and Ullmann reactions were rapid and provided good to excellent yields.
  • Publication
    Transition-metal-free a-arylation of enolizable aryl ketones and mechanistic evidence for a radical process
    (John Wiley & Sons, Inc., 2015-07-01) Ollevier, Thierry; Fabre, Indira; Pichette Drapeau, Martin; Grimaud, Laurence; Ciofini, Ilaria; Taillefer, Marc
    The a-arylation of enolizable aryl ketones can be carried out with aryl halides under transition-metal-free conditions using KOtBu in DMF. The a-aryl ketones thus obtained can be used for step- and cost-economic syntheses of fused heterocycles and Tamoxifen. Mechanistic studies demonstrate the synergetic role of base and solvent for the initiation of the radical process.
  • Publication
    Accès libre
    New chiral bis(oxazolinyl) bipyridine ligands and application in the iron catalyzed asymmetric hydrosilylation of ketones
    (Taras Shevchenko National University of Kyiv., 2015-12-01) Ollevier, Thierry; Levitre, Guillaume; Keipour, Hoda; Jalba, Angela; Lauzon, Samuel
    C2 symmetrical 6,6'-bis(oxazolinyl)-2,2'-bipyridine (bipybox) chiral ligands have been synthesized from readily available 2,2'-bipyridine. Catalytic asymmetric hydrosilylation of ketones was studied using this family of ligands in the presence of iron(II) acetate.
  • Publication
    Iron(II)-derived Lewis acid/surfactant combined catalysis for the enantioselective Mukaiyama aldol reaction in pure water
    (Wiley, 2014-06-26) Lafantaisie, Mathieu; Ollevier, Thierry; Mirabaud, Anaïs; Plancq, Baptiste
    The catalytic asymmetric Mukaiyama aldol reaction in pure water was performed by using a combination of iron(II) dodecyl sulfate, a chiral bipyridine ligand, and benzoic acid. By using the obtained iron(II)-derived Lewis acid/surfactant combined catalyst, the desired products were afforded in good yields with high diastereo- and enantioselectivities.
  • Publication
    Accès libre
    Enantioselective aromatic sulfide oxidation and tandem kinetic resolution using aqueous H2O2 and chiral iron Bis(oxazolinyl)bipyridine catalysts
    (Wiley-VCH-Verl, 2016-12-27) Ollevier, Thierry; Régnier, Noémie; Jalba, Angela
    An efficient method for the oxidation of aromatic sulfides was developed using aqueous H2O2 catalyzed by in situ-generated chiral Fe/6,6'-bis(oxazolinyl)-2,2'-bipyridine (bipybox) complex. The corresponding sulfoxides were obtained in high enantio-selectivities (up to 98.5:1.5 er) and good yields (up to 61%) when the mono-oxidation of the sulfides was performed in combination with the kinetic resolution of the sulfoxide into the sulfone.