Frédéric Caijo
École Normale Supérieure
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Featured researches published by Frédéric Caijo.
Green Chemistry | 2011
Rubén Duque; Eva Öchsner; Hervé Clavier; Frédéric Caijo; Steven P. Nolan; Marc Mauduit; David J. Cole-Hamilton
Continuous flow homogeneous alkene metathesis using a supported ionic liquid phase (SILP) catalyst with CO2 as a transport vector allows the self-metathesis of methyl oleate with only a slight loss of activity for at least 10 h; cross-metathesis of dimethyl maleate with methyl oleate ceases after 3 h, but the catalyst remains active for methyl oleate metathesis. The reasons for this unusual behaviour are explored and a practical system for the cross-metathesis of methyl oleate with dimethyl maleate, under batch conditions, is described.
Chemistry: A European Journal | 2012
Etienne Borré; Mathieu Rouen; Isabelle Laurent; Magaly Magrez; Frédéric Caijo; Christophe Crévisy; Wladimir Solodenko; Loïc Toupet; René Frankfurter; Carla Vogt; Andreas Kirschning; Marc Mauduit
In this study, a new pyridinium-tagged Ru complex was designed and anchored onto sulfonated silica, thereby forming a robust and highly active supported olefin-metathesis pre-catalyst for applications under batch and continuous-flow conditions. The involvement of an oxazine-benzylidene ligand allowed the reactivity of the formed Ru pre-catalyst to be efficiently controlled through both steric and electronic activation. The oxazine scaffold facilitated the introduction of the pyridinium tag, thereby affording the corresponding cationic pre-catalyst in good yield. Excellent activities in ring-closing (RCM), cross (CM), and enyne metathesis were observed with only 0.5 mol % loading of the pre-catalyst. When this powerful pre-catalyst was immobilized onto a silica-based cationic-exchange resin, a versatile catalytically active material for batch reactions was generated that also served as fixed-bed material for flow reactors. This system could be reused at 1 mol % loading to afford metathesis products in high purity with very low ruthenium contamination under batch conditions (below 5 ppm). Scavenging procedures for both batch and flow processes were conducted, which led to a lowering of the ruthenium content to as little as one tenth of the original values.
Chemical Communications | 2007
Diane Rix; Frédéric Caijo; Isabelle Laurent; Lukasz Gulajski; Karol Grela; Marc Mauduit
Whereas the boomerang ligand of Hoveyda-Grubbs pre-catalysts can be modified by attachment of a pyridinium tag to its benzylidene moiety, a precise adjustment of the length of the spacer allows the optimum balance to be reached between the activity of the catalyst and its recoverability, exceeding 98% after 6 catalytic runs in the best case.
Catalysis Science & Technology | 2013
Frédéric Caijo; Fabien Tripoteau; Aurélien Bellec; Christophe Crévisy; Olivier Baslé; Marc Mauduit; Oliver Briel
A library of thirteen different commercially available Ru-based catalysts was evaluated in valuable metathesis reactions for the production of fragrance and bioactive molecule precursors. Rigorous library screening clearly illustrated the different catalytic behaviour of the catalyst selection and highlighted its significant advantage to provide efficiency in specific metathesis applications. Interestingly, this strategy offered substantial improvement over the state of the art, with the efficient synthesis of the macrocyclic Exaltolide 2 at low catalyst loading and dilution conditions.
Chemsuschem | 2014
Nathalie Clousier; Alexandra Filippi; Etienne Borré; Eric Guibal; Christophe Crévisy; Frédéric Caijo; Marc Mauduit; Isabelle Dez; Annie-Claude Gaumont
Original ruthenium supported ionic liquid phase (SILP) catalysts based on alginates as supports were developed for olefin metathesis reactions. The marine biopolymer, which fulfills most of the requisite properties for a support such as widespread abundance, insolubility in the majority of organic solvents, a high affinity for ionic liquids, high chemical stability, biodegradability, low cost, and easy processing, was impregnated by [bmim][PF6 ] containing an ionically tagged ruthenium catalyst. These biosourced catalysts show promising performances in ring-closing metathesis (RCM) and cross-metathesis (CM) reactions, with a high level of recyclability and reusability combined with a good reactivity.
Topics in Catalysis | 2014
Angelino Doppiu; Frédéric Caijo; Fabien Tripoteau; Savinien Bompard; Christophe Crévisy; Marc Mauduit
Olefin metathesis is a powerful catalytic reaction that has a huge potential in the pharmaceutical, polymer and specialty chemicals industries. Cost-effective industrial applications require large-scale availability of catalyst precursors which combine high activity, high selectivity and long life-time. Among the known numerous families of olefin metathesis catalysts, the Umicore M7-catalyst family represents a novel class of Hoveyda-type complexes showing excellent chemical stabilities and modular activity profiles. Relevant aspects related to their industrial synthesis as well as their catalytic performance in valuable olefin metathesis transformations are overviewed here.
Beilstein Journal of Organic Chemistry | 2010
Etienne Borré; Frédéric Caijo; Christophe Crévisy; Marc Mauduit
Summary Seven novel Hoveyda–Grubbs precatalysts bearing an aminosulfonyl function are reported. Kinetic studies indicate an activity enhancement compared to Hoveyda’s precatalyst. A selection of these catalysts was investigated with various substrates in ring-closing metathesis of dienes or enynes and cross metathesis. The results demonstrate that these catalysts show a good tolerance to various chemical functions.
Chemistry: A European Journal | 2017
Jessica Allard; Idriss Curbet; Guillaume Chollet; Fabien Tripoteau; Sophie Sambou; Frédéric Caijo; Yann Raoul; Christophe Crévisy; Olivier Baslé; Marc Mauduit
A practical and cost-effective ruthenium-catalyzed self-metathesis of non-refined methyl oleate (85 %) derived from very high oleic sunflower oils was demonstrated at pilot scale using a robust and kg-scale commercially available SIPr-M71 pre-catalyst. The simple addition of 1 wt % bleaching earths (Tonsil 110FF) to a thermally pretreated oil could efficiently prevent catalyst deactivation. Remarkably, without the need for filtration, the catalytic system was able to achieve a turnover number (TON) of more than 744 000 at a catalyst loading of only 1 ppm. At large scale (up to 200 kg), the equilibrium of the self-metathesis reaction was reached within 1 hour at 50 °C under neat conditions at a very low 5 ppm catalyst loading to produce the expected primary metathesis products (PMP), that is, 9-octadecene and dimethyl-9-octadecenoate, with a productive TON of 94900.
Journal of Enzyme Inhibition and Medicinal Chemistry | 2010
Mélanie Liutkus; Frédéric Caijo; Anne-Lise Girard; Erwan Ayral; Valérie Audinot; Jean A. Boutin; Pierre Renard; Daniel Henri Caignard; Catherine Dacquet; Alain Ktorza; Paul Mosset; René Grée
Structural modifications around 8-HETE (8-hydroxyeicosatetraenoic acid), a natural agonist of the PPAR (peroxisome proliferator-activated receptor) nuclear receptors have led previously to the identification of a promising analog, the quinoline S 70655. Series of novel quinoline or benzoquinoline derivatives were designed through the modification of this lead. Variations of the nature of the aromatic core and of the side chains were carried out. The SAR studies indicated the high sensitivity of the upper acid chain to modifications as well as the strong effect of the length and size of the lipophilic side chain. They afforded several new promising PPARα/γ dual agonists with a high PPARα activity in vitro.
Journal of Organic Chemistry | 2008
Diane Rix; Frédéric Caijo; Isabelle Laurent; Fabien Boeda; Hervé Clavier; Steven P. Nolan; Marc Mauduit