Le centre de Villeurbanne en 1934 et 2014.

Intervention au forum "Le centre : la ville ; les centres : la métropole" à l'occasion du 80e anniversaire des Gratte-Ciel, place Goujon, Villeurbanne

Imidazolium and Potassium Hydrogen Carbonate Salts as Ecofriendly Organocatalysts for Oxazolidinone Synthesis

International audienceAlthough oxazolidinones are valuable intermediate compounds for industrial applications, no synthetic method is suitable for their production on a large scale owing to the use of reagents/catalysts that are hazardous or toxic to human health or ecotoxic for the environment. In this manuscript, we describe new and efficient catalysts, that is, the nontoxic hydrogen carbonate anion in combination with a potassium or diisobutylimidazolium ([iBu(2)IM]) countercation, for the conversion of -amino alcohols into cyclic oxazolidinones in high yields of 69 to 90%. Depending on the catalytic conditions, both catalysts could be easily recovered from the crude reaction products and reused several times without a decrease in their catalytic performance. Furthermore, the imidazolium cation is a renewable catalyst, because its preparation requires less than 10% of carbon fossil sources

Aromatic Nucleophilic Substitution (SNAr) of meso-Nitroporphyrin with Azide and Amines as an Alternative Metal Catalyst Free Synthetic Approach To Obtain meso-N-Substituted Porphyrins

International audienceAromatic nucleophilic substitution reaction of the nitro group of meso-nitroporphyrins with azide and various amines was achieved and represents an alternative procedure to C-N coupling reactions usually needed to obtain such meso-N-substituted porphyrins in good yields

Kinetic and Electrochemical Studies of the Oxidative Addition of Demanding Organic Halides to Pd(0): the Efficiency of Polyphosphane Ligands in Low Palladium Loading Cross-Couplings Decrypted

International audienceOxidative addition (OA) of organic halides to palladium(0) species is a fundamental reaction step which initiates the C–C bond formation catalytic processes typical of Pd(0)/Pd(II) chemistry. The use of structurally congested polyphosphane ligands in palladium-catalyzed C–C bond formation has generated very high turnover numbers (TONs) in topical reactions such as Heck, Suzuki, Sonogashira couplings, and direct sp2C–H functionalization. Herein, the OA of aryl bromides to Pd(0) complexes stabilized by ferrocenylpolyphosphane ligands L1 (tetraphosphane), L2 (triphosphane), and L3 (diphosphane) is considered. The investigation of kinetic constants for the addition of Ph–Br to Pd(0) intermediates (generated by electrochemical reduction of Pd(II) complexes coordinated by L1–L3) is reported. Thus, in the OA of halides to the Pd(0) complex coordinated by L1 the series of rate constants kapp is found (mol–1 L s–1): kapp(Ph–Br) = 0.48 > kapp(ClCH2–Cl) = 0.25 ≫ kapp(p-MeC6H4–Br) = 0.08 ≈ kapp(o-MeC6H4–Br) = 0.07 ≫ kapp(Ph–Cl). Kinetic measurements clarify the influence that the presence of four, three, or two phosphorus atoms in the coordination sphere of Pd has on OA. The presence of supplementary phosphorus atoms in L1 and L2 unambiguously stabilizes Pd(0) species and thus slows down the OA of Ph–Br to Pd(0) of about 2 orders of magnitude compared to the diphosphane L3. The electrosynthesis of the complexes resulting from the OA of organic halides to [Pd(0)/L] is easily performed and show the concurrent OA to Pd(0) of the sp3C–Cl bond of dichloromethane solvent. The resulting unstable Pd/alkyl complex is characterized by NMR and single crystal X-ray structure. We additionally observed the perfect stereoselectivity of the OA reactions which is induced by the tetraphosphane ligand L1. Altogether, a clearer picture of the general effects of congested polydentate ligands on the OA of organic halides to Pd(0) is given

Aromatic Nucleophilic Substitution (S_NAr) of <i>meso</i>-Nitroporphyrin with Azide and Amines as an Alternative Metal Catalyst Free Synthetic Approach To Obtain <i>meso</i>-<i>N</i>‑Substituted Porphyrins

Aromatic nucleophilic substitution reaction of the nitro group of <i>meso</i>-nitroporphyrins with azide and various amines was achieved and represents an alternative procedure to C–N coupling reactions usually needed to obtain such <i>meso</i>-<i>N</i>-substituted porphyrins in good yields

Aromatic Nucleophilic Substitution (S_NAr) of <i>meso</i>-Nitroporphyrin with Azide and Amines as an Alternative Metal Catalyst Free Synthetic Approach To Obtain <i>meso</i>-<i>N</i>‑Substituted Porphyrins

Aromatic nucleophilic substitution reaction of the nitro group of <i>meso</i>-nitroporphyrins with azide and various amines was achieved and represents an alternative procedure to C–N coupling reactions usually needed to obtain such <i>meso</i>-<i>N</i>-substituted porphyrins in good yields

Electrosynthesis of Imidazolium Carboxylates

Synthesis of imidazolium carboxylate compounds was efficiently achieved by electrochemical reduction of imidazolium precursors under very mild conditions

Ruthenium and Osmium Complexes of Phosphine-Porphyrin Derivatives as Potential Bimetallic Theranostics: Photophysical Studies

A series of (η⁶-<i>p</i>-cymene)­ruthenium­(II)- and osmium­(II) complexes of porphyrin-phosphane derivatives have been synthesized as potential bimetallic theranostic candidates. The photophysical and electrochemical properties were investigated, and these species desirably exhibit no or almost no photoinduced intramolecular atom, energy, and electron transfer between the dye and the metallic fragment. These favorable features are mostly associated with the presence of their long chain (i.e., ∼ 1 nm) separating the two functional units. Interestingly, a decrease in emission intensity and lifetimes (up to 35-fold) has been observed, which was ascribed to a small heavy atom effect. This effect is possible as a chain folding driven by an intramolecular H-bond (N–H···Cl–M)

Kinetic and Electrochemical Studies of the Oxidative Addition of Demanding Organic Halides to Pd(0): the Efficiency of Polyphosphane Ligands in Low Palladium Loading Cross-Couplings Decrypted

Oxidative addition (OA) of organic halides to palladium(0) species is a fundamental reaction step which initiates the C–C bond formation catalytic processes typical of Pd(0)/Pd­(II) chemistry. The use of structurally congested <i>polyphosphane</i> ligands in palladium-catalyzed C–C bond formation has generated very high turnover numbers (TONs) in topical reactions such as Heck, Suzuki, Sonogashira couplings, and direct sp²C–H functionalization. Herein, the OA of aryl bromides to Pd(0) complexes stabilized by ferrocenylpolyphosphane ligands <b>L1</b> (tetraphosphane), <b>L2</b> (triphosphane), and <b>L3</b> (diphosphane) is considered. The investigation of kinetic constants for the addition of Ph–Br to Pd(0) intermediates (generated by electrochemical reduction of Pd­(II) complexes coordinated by <b>L1</b>–<b>L3</b>) is reported. Thus, in the OA of halides to the Pd(0) complex coordinated by <b>L1</b> the series of rate constants <i>k</i>_app is found (mol^–1 L s^–1): <i>k</i>_app(Ph–Br) = 0.48 > <i>k</i>_app(ClCH₂–Cl) = 0.25 ≫ <i>k</i>_app(<i>p</i>-MeC₆H₄–Br) = 0.08 ≈ <i>k</i>_app(<i>o</i>-MeC₆H₄–Br) = 0.07 ≫ <i>k</i>_app(Ph–Cl). Kinetic measurements clarify the influence that the presence of four, three, or two phosphorus atoms in the coordination sphere of Pd has on OA. The presence of supplementary phosphorus atoms in <b>L1</b> and <b>L2</b> unambiguously stabilizes Pd(0) species and thus slows down the OA of Ph–Br to Pd(0) of about 2 orders of magnitude compared to the diphosphane <b>L3</b>. The electrosynthesis of the complexes resulting from the OA of organic halides to [Pd(0)/<b>L</b>] is easily performed and show the concurrent OA to Pd(0) of the sp³C–Cl bond of dichloromethane solvent. The resulting unstable Pd/alkyl complex is characterized by NMR and single crystal X-ray structure. We additionally observed the perfect stereoselectivity of the OA reactions which is induced by the tetraphosphane ligand <b>L1</b>. Altogether, a clearer picture of the general effects of congested polydentate ligands on the OA of organic halides to Pd(0) is given