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Accueil > Les équipes > Méthodes et Applications en Chimie Organique (MACO) > Publications

Publications

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2022



  • V. Corcé, C. Ollivier, et L. Fensterbank, « Boron, silicon, nitrogen and sulfur-based contemporary precursors for the generation of alkyl radicals by single electron transfer and their synthetic utilization », Chemical Society Reviews, vol. 51, nᵒ 4, p. 1470-1510, févr. 2022.
    Résumé : Recent developments in the use of boron, silicon, nitrogen and sulfur derivatives in single-electron transfer reactions for the generation of alkyl radicals are described. Photoredox catalyzed, electrochemistry promoted or thermally-induced oxidative and reductive processes are discussed highlighting their synthetic scope and discussing their mechanistic pathways.
    Mots-clés : CHEMBIO, MACO, POLE 1, POLE 3.

2021



  • T. Deis, F. Medici, A. Poussard-Schulz, G. Lemière, et L. Fensterbank, « Synthesis and reactivity of an anionic NHC-borane featuring a weakly coordinating silicate anion », Journal of Organometallic Chemistry, vol. 956, p. 122120, déc. 2021.
    Résumé : We report herein the synthesis of a new NHC-stabilised borane complex featuring a weakly coordinating anion, namely a pentaorganosilicate, on the NHC backbone. The synthesis can be achieved from a zwitterionic abnormal silicate-imidazolium adduct by deprotonation with a strong base followed by quenching with a borane transfer agent. Alternatively, the IPr-BH3 complex can also be deprotonated and the resulting vinylanion is trapped by a tetravalent spirosilane. The first structural data on a lithium derivative of an anionic NHC-borane complex functionalized by a silicate have been obtained and reveal an interaction between the three hydrogens of the borane and the lithium cation. Assessment of the reactivity highlights the higher hydridicity of the anionic NHC-borane compared to the parent IPr-BH3. Finally, electronic properties of this new species have been evaluated by means of DFT calculations and the presence of the silicate on the NHC backbone raises the HOMO which can in part explain the high hydride-donor abilities. This is consistent with the smooth reduction of an aldehyde without Lewis acid additive.
    Mots-clés : Anionic NHC, DFT calculations, MACO, NHC-borane, Pentacoordinated compounds, POLE 1, Silicon, Spirosilane.


  • E. Levernier, K. Jaouadi, H. - R. Zhang, V. Corcé, A. Bernard, G. Gontard, C. Troufflard, L. Grimaud, E. Derat, C. Ollivier, et L. Fensterbank, « Phenyl Silicates with Substituted Catecholate Ligands: Synthesis, Structural Studies and Reactivity », Chemistry – A European Journal, vol. 27, nᵒ 34, p. 8782-8790, 2021.
    Résumé : While the generation of aryl radicals by photoredox catalysis under reductive conditions is well documented, it has remained challenging under an oxidative pathway. Because of the easy photo-oxidation of alkyl bis-catecholato silicates, a general study of phenyl silicates bearing substituted catecholate ligands has been achieved. The newly synthesized phenyl silicates have been fully characterized, and their reactivity has been explored. It was found that, thanks to the substitution of the catecholate moiety, notably with the 4-cyanocatecholato ligand, the phenyl radical could be generated and trapped. Computational studies provided a rationale for these findings.
    Mots-clés : aryl radicals, CHEMBIO, MACO, oxidation, photoredox catalysis, POLE 1, POLE 3, silicates.


  • B. Neil, F. Lucien, L. Fensterbank, et C. Chauvier, « Transition-Metal-Free Silylation of Unactivated C(sp2)–H Bonds with tert-Butyl-Substituted Silyldiazenes », ACS Catalysis, vol. 11, nᵒ 21, p. 13085-13090, nov. 2021.
    Résumé : Aromatic organosilanes bearing C(sp2)–Si bonds have found increasing applications across the chemical science, yet are mostly produced by atom-uneconomical stoichiometric procedures. Catalytic alternatives using hydrosilanes as silicon sources have also been described, but they display unfavorable thermodynamics and are mostly based on expensive catalytic systems, often derived from noble metals, or lack generality. Herein, we describe the use of an alternative silicon source, namely the tert-butyl-substituted silyldiazenes (tBu–N═N–SiR3), that are readily accessible from commercially available precursors and whose structure enables the C(sp2)–H bond silylation of unactivated heteroaryl and aryl compounds under ambient, transition-metal-free catalytic conditions.
    Mots-clés : MACO, POLE 1.

2020


  • Y. Ren, J. Forte, K. Cheaib, N. Vanthuyne, L. Fensterbank, H. Vezin, M. Orio, S. Blanchard, et M. Desage-El Murr, « Optimizing Group Transfer Catalysis by Copper Complex with Redox-Active Ligand in an Entatic State », Iscience, vol. 23, nᵒ 3, p. UNSP 100955, mars 2020.
    Résumé : Metalloenzymes use earth-abundant non-noble metals to perform high-fidelity transformations in the biological world. To ensure chemical efficiency, metalloenzymes have acquired evolutionary reactivity-enhancing tools. Among these, the entatic state model states that a strongly distorted geometry induced by ligands around a metal center gives rise to an energized structure called entatic state, strongly improving the reactivity. However, the original definition refers both to the transfer of electrons or chemical groups, whereas the chemical application of this concept in synthetic systems has mostly focused on electron transfer, therefore eluding chemical transformations. Here we report that a highly strained redox-active ligand enables a copper complex to perform catalytic nitrogen- and carbon-group transfer in as fast as 2 min, thus exhibiting a strong increase in reactivity compared with its unstrained analogue. This report combines two reactivity-enhancing features from metalloenzymes, entasis and redox cofactors, applied to group-transfer catalysis.
    Mots-clés : aziridination, cu, E-POM, galactose-oxidase, generation, MACO, metal-complexes, models, oxidation, POLE 1, POLE 2, radicals, reactivity, site.

2019



  • V. Corcé, C. Lévêque, C. Ollivier, et L. Fensterbank, « 15 Silicates in Photocatalysis », in Photocatalysis in Organic Synthesis, 1st editionᵉʳ éd., Thieme Verlag, 2019.
    Résumé : Bis(catecholato)silicates have emerged as robust alkyl radical sources under photocatalysis. This chapter describes the preparation of various silicates and their utilization under photocatalytic conditions for the formation of C–C and C–O bonds. The last section focuses on the use of silicates in photoredox/nickel dual catalysis.
    Mots-clés : CHEMBIO, MACO, POLE 3.
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