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  • S. Curpanen, G. Poli, A. Perez-Luna, et J. Oble, « C3−H Silylation of Furfurylimines: Direct Access to a Novel Biobased Versatile Synthetic Platform Derived from Furfural », Asian Journal of Organic Chemistry, vol. 11, nᵒ 7, p. e202200199, 2022.
    Résumé : Herein we report directed iridium-catalyzed C3−H silylation of furfuryl imines, which grants access to versatile synthetic platforms. This transformation was developed on furfuryl derivatives, using imines as directing groups, and trialkylsilanes or bis(trimethylsilyl)methylsilane as silylating agents, in the presence of a hydride scavenger. Subsequently, fluoride-mediated activation strategies were applied to the C3−SiMe(OSiMe3)2 furfural derivatives to achieve a wide range of transformations of the C3−Si bond. Arylation, alkenylation, alkynylation, allylation and alkylation, as well as halogenation and trifluoromethylation were achieved in modest to high yields. A variety of high value-added products were thus easily obtained from the same common C3-silylated furfural-based platform.
    Mots-clés : Biomass, Fluoride, Furfural, Iridium, POLE 1, ROCS, Silicon.

  • S. Curpanen, P. Reichert, G. Lupidi, G. Poli, J. Oble, et A. Perez-Luna, « Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C–Si bond functionalization », Beilstein Journal of Organic Chemistry, vol. 18, nᵒ 1, p. 1256-1263, sept. 2022.
    Résumé : Beilstein Journal of Organic Chemistry
    Mots-clés : POLE 1, ROCS.

  • D. Illuminati, A. Fantinati, T. De Ventura, D. Perrone, C. Sturaro, V. Albanese, E. Marzola, V. Cristofori, J. Oble, G. Poli, et C. Trapella, « Synthesis of 2,6-Dimethyltyrosine-Like Amino Acids through Pinacolinamide-Enabled C–H Dimethylation of 4-Dibenzylamino Phenylalanine », The Journal of Organic Chemistry, vol. 87, nᵒ 5, p. 2580-2589, mars 2022.
    Résumé : The synthesis of a small library of NH-Boc- or NH-Fmoc-protected l-phenylalanines carrying methyl groups at positions 2 and 6 and diverse functionalities at position 4 has been achieved. The approach, which took advantage of a Pd-catalyzed directed C–H dimethylation of picolinamide derivatives, allowed the electronic and steric properties of the resulting amino acid derivatives to be altered by appending a variety of electron-withdrawing, electron-donating, or bulky groups.
    Mots-clés : POLE 1, ROCS.

  • S. Kassamba, A. Perez-Luna, F. Ferreira, et M. Durandetti, « Modular access to substituted germoles by intramolecular germylzincation », Chemical Communications, vol. 58, nᵒ 24, p. 3901-3904, mars 2022.
    Résumé : Intramolecular alkyne germylzincation giving access to a wide range of germoles is achieved from triarylhydrogermanes in the presence of diethylzinc and AIBN as radical initiator. The reaction proceeds through activation of the Ge–H bond, leading to a heteroarylzinc intermediate after cyclisation, which can then be involved in a post-functionalisation reaction. Our results show that only 5-endo-dig cyclizations occur, with benzogermoles being exclusively obtained.
    Mots-clés : POLE 1, ROCS.

  • A. Mori, S. Curpanen, C. Pezzetta, A. Perez-Luna, G. Poli, et J. Oble, « C−H Activation Based Functionalization of Furfural Derivatives », European Journal of Organic Chemistry, vol. n/a, nᵒ n/a, p. e202200727, 2022.
    Résumé : Furfural and related compounds are building blocks of industrial interest, obtained from raw biomass. Their use as precursors of basic and fine chemicals has gained increasing attention as a green alternative to petroleum-derived compounds. Several works have reported the functionalization of furfurals to obtain a wider range of chemicals, opening up new synthetic possibilities and applications, ranging from biofuels to pharmaceuticals. Among these works, processes based on C−H activation are the most attractive ones for their atom economy and the possibility to use non-activated substrates. This minireview summarizes the reported methods of direct C−H functionalization of furfurals without prior modification of the redox state of the aldehyde function. In particular, the transition metal catalyzed functionalization of each bond of the heteroaromatic nucleus of these molecules is systematically discussed, as well as examples of C−H transformations of the aldehyde function.
    Mots-clés : Biomass, Catalysis, C−H Activation, Furfural, POLE 1, ROCS, Transition metal.

  • R. Sala, G. Kiala, L. F. Veiros, G. Broggini, G. Poli, et J. Oble, « Redox-Neutral Ru(0)-Catalyzed Alkenylation of 2-Carboxaldimine-heterocyclopentadienes », The Journal of Organic Chemistry, vol. 87, nᵒ 7, p. 4640-4648, avr. 2022.
    Résumé : A new Ru3(CO)12-catalyzed directed alkenylation of 2-carboxaldimine-heterocyclopentadienes has been accomplished. This process allows coupling of furan, pyrrole, indole, and thiophene 2-carboxaldimines with electron-poor alkenes such as acrylates, vinylsulfones, and styrenes. This regio- and chemoselective oxidative C–H coupling does not require the presence of an additional sacrificial oxidant. Density functional theory calculations allowed us to propose a mechanism and unveiled the nature of the H2 acceptor.
    Mots-clés : POLE 1, ROCS.


  • F. Carlet, G. Bertarini, G. Broggini, A. Pradal, et G. Poli, « Oxoammonium-Mediated Allylsilane–Ether Coupling Reaction », European Journal of Organic Chemistry, vol. 2021, nᵒ 15, p. 2162-2168, 2021.
    Résumé : A new C(sp3)−H functionalization reaction consisting of the oxidative α-allylation of allyl- and benzyl- methyl ethers has been developed. The C−C coupling could be carried out under mild conditions thanks to the use of cheap and green oxoammonium salts. The scope of the reaction was studied over 27 examples, considering the nature of the substituents on the two coupling partners.
    Mots-clés : Allylation, Benzyl ethers, C(sp3)−H functionalization, Cinnamyl ethers, Oxoammonium, ROCS.

  • F. Chemla et A. Perez-Luna, « 2.5 Radical–Polar Crossover Reactions », in Free Radicals: Fundamentals and Applications in Organic Synthesis 2, 2021ᵉʳ éd., Thieme Verlag, 2021.
    Résumé : Radical–polar crossover reactions, that is, single-electron redox events allowing for the interconversion between radical and ionic intermediates, make it possible to connect radical and polar processes in the same synthetic transformation. Such a combination is the basis of much original synthetic methodology, which is particularly useful in the context of domino, tandem, or multicomponent reactions. This chapter comprehensively covers the field of radical–polar crossover reactions, with a primary emphasis on transformations wherein both the radical and polar processes provide synthetic elaboration.
    Mots-clés : Organic Chemistry, POLE 1, ROCS.
    Pièce jointe Snapshot 617.9 ko (source)

  • S. Curpanen, G. Poli, J. Oble, et A. Perez‐Luna, « C(sp2)−Si Bond Functionalization through Intramolecular Activation by Alkoxides », European Journal of Organic Chemistry, vol. 2021, nᵒ 7, p. 1055-1071, 2021.
    Résumé : Organosilicon reagents are invaluable tools in the hands of the modern chemist that allow accomplishing a number of synthetically useful transformations. While some are standard reactions, others are more complex transformations, such as the Brook rearrangement and its variants. This carbon-to-oxygen silyl migration represents a privileged method to generate transient carbanionic species well suited to undergo functionalization upon electrophilic substitution in the presence of an electrophile. This minireview focuses on recent advances in C(sp2)−Si bond functionalization through intramolecular activation by alkoxides. The key elements of reactivity will be highlighted in the introduction to allow the proper understanding of the migration process. Then, an overview of the reactivity of substrates incorporating the C(sp2)−Si motif and their synthetic applications will be provided.
    Mots-clés : Anion Relay Chemistry, Brook rearrangement, Hiyama cross-coupling, POLE 1, ROCS, Silyl migration, Synthetic methods.
    Pièce jointe Snapshot 484.1 ko (source)

  • K. de la Vega-Hernández, F. Chemla, F. Ferreira, O. Jackowski, et A. Perez-Luna, « Radical Germylzincation of Aryl- and Alkyl-Substituted Internal Alkynes », Organic Letters, vol. 23, nᵒ 11, p. 4426-4430, juin 2021.
    Résumé : The stereoselective germylzincation of internal alkynes delivering trisubstituted vinylgermanes is achieved via a radical chain process involving Ph3GeH and Et2Zn with AIBN as the initiator. Excellent levels of regiocontrol are observed for nonsymmetric (aryl, alkyl)-substituted alkynes and for propargylic alcohols with aryl-, alkyl-, or silyl-substituted alkynes. The germylzincation reaction can be combined in one pot with the Cu(I)-mediated electrophilic substitution of the C(sp2)–Zn bond to obtain synthetically challenging tetrasubstituted vinylgermanes.
    Mots-clés : POLE 1, ROCS.

  • K. de la Vega-Hernández, K. Isaac, F. Chemla, F. Ferreira, O. Jackowski, et A. Perez-Luna, « Radical Silyl- and Germylzincation of Propargylic Alcohols », Helvetica Chimica Acta, vol. 104, nᵒ 10, p. e2100128, 2021.
    Résumé : The silyl- and germylzincation of terminal or internal propargylic alcohols by reaction with (Me3Si)3SiH/Et2Zn, [(Me3Si)3Si]2Zn/Et2Zn or Ph3GeH/Et2Zn is examined. These reactions proceed through the addition of silicon- or germanium-centered radicals across the carbon≡carbon triple bond followed by the trapping by diethylzinc of the produced vinyl radical through homolytic substitution at the zinc atom. The influence of the hydroxy unit on the regio- and stereoselectivity of these reactions is discussed and compared to its role played in radical hydrosilylation and hydrogermylation reactions. Protocols developed to achieve the β-regioselective silylzincation of propargyl alcohol and the α-regioselective germylzincation of internal propargylic alcohols are particularly important, as they occur with trans stereoselectivity. For both procedures the C(sp2)−Zn bond remains available for subsequent in-situ electrophilic substitution leading overall to net alkyne trans difunctionalization.
    Mots-clés : germanium, germylmetalation, POLE 1, propargylic alcohols, radical reactions, ROCS, silylmetalation, zinc.

  • E. Romain, K. de la Vega-Hernández, F. Guégan, J. S. García, C. Fopp, F. Chemla, F. Ferreira, H. Gerard, O. Jackowski, S. Halbert, M. Oestreich, et A. Perez-Luna, « Development of a Radical Silylzincation of (Het)Aryl-Substituted Alkynes and Computational Insights into the Origin of the trans-Stereoselectivity », Advanced Synthesis & Catalysis, vol. 363, nᵒ 10, p. 2634-2647, 2021.
    Résumé : Aryl- and hetaryl-substituted acetylenes undergo regio- and stereoselective silylzincation by reaction with [(Me3Si)3Si]2Zn in the presence of Et2Zn (10–110 mol%) as additive. The distinctive feature of this addition across the C−C triple bond is its trans stereoselectivity. The radical nature of the silylzincation process is supported by diagnostic experiments and DFT calculations, which also corroborate the role played by steric effects to obtain that stereoselectivity. The procedure can be combined in one-pot with the copper(I)-mediated electrophilic substitution of the C(sp2)−Zn bond, with retention of the double bond geometry. This makes it valuable for the synthesis of stereodefined di- and trisubstituted vinylsilanes.
    Mots-clés : POLE 1, Radical reactions, ROCS, Silylmetalation, Silylzinc reagents, Vinylsilanes, Zinc.
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  • G. Bouhalleb, A. Meddeb, N. F. Bourguiba, J. Legros, G. Poli, et F. Rezgui, « First Zinc Bromide Promoted Annulative Domino Reactions between Enamines and Cyclic Morita–Baylis–Hillman Alcohols: Synthesis of N,O-Ketals », Synlett, vol. 31, nᵒ 13, p. 1282-1286, août 2020.
    Résumé : A new efficient ZnBr2-mediated annulative domino reaction between enamines and cyclic Morita–Baylis–Hillman (MBH) alcohols is disclosed. The process involves a tandem sequence (intermolecular conjugate addition of enamines to MBH alcohols and intramolecular nucleophilic addition of the hydroxyl moiety to the transiently generated iminium ion), affording the corresponding N,O-ketals diastereoselectively in good yields.
    Mots-clés : conjugate addition, domino reactions, enamines, ketals, Key words MBH alcohol, N,O, POLE 1, ROCS, zinc bromide.
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  • F. Foschi, C. Loro, R. Sala, J. Oble, L. Lo Presti, E. M. Beccalli, G. Poli, et G. Broggini, « Intramolecular Aminoazidation of Unactivated Terminal Alkenes by Palladium-Catalyzed Reactions with Hydrogen Peroxide as the Oxidant », Organic Letters, vol. 22, nᵒ 4, p. 1402-1406, févr. 2020.
    Résumé : The palladium-catalyzed aminoazidation of aminoalkenes yielding azidomethyl-substituted nitrogen-containing heterocycles was developed. The procedure requires oxidative conditions and occurs at room temperature in the presence of hydrogen peroxide and NaN3 as the azide source. These conditions provide selective exo-cyclization/azidation of the carbon–carbon double bond, furnishing a versatile approach toward five-, six-, and seven-membered heterocyclic rings.
    Mots-clés : POLE 1, ROCS.
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  • Y. Liu, J. Oble, A. Pradal, et G. Poli, « Catalytic Domino Annulations through η3-Allylpalladium Chemistry: A Never-Ending Story », European Journal of Inorganic Chemistry, vol. 2020, nᵒ 11-12, p. 942-961, 2020.
    Résumé : Annulative η3-allylpalladium chemistry has been a longstanding trending research topic since the 80's. Nowadays, this research area is still providing challenges to the catalysis community leading to the development original and brand-new transformations. Several reaction partners have been used as precursors for η3-allylpalladium species, namely allyl diacetates, allyl monoacetates, 3-acetoxy-2-trimethylsilylmethyl-1-propene (ASMP), alkylidene cyclopropanes (ACPs), vinyl cyclopropanes (VCPs), vinyl aziridines, and vinyl epoxides. This minireview is intended to show the recent developments in the field of annulative η3-allylpalladium chemistry with emphasis on new reactivity, enantioselective transformations as well as potential applications in total synthesis.
    Mots-clés : POLE 1, ROCS.

  • J. A. C. Oliveira, G. Kiala, F. Siopa, A. Bernard, G. Gontard, J. Oble, C. A. M. Afonso, et G. Poli, « Palladium-catalyzed allylic substitution between C-based nucleophiles and 6-azabicyclo[3.1.0]-hex-3-en-2-oxy derivatives: A new selectivity paradigm », Tetrahedron, vol. 76, nᵒ 51, p. 131182, déc. 2020.
    Résumé : The reaction between α-hydroxy-(or α-acetoxy) cyclopenten-aziridines (6-azabicyclo[3.1.0]hex-3-en-2-ols or acetates) and C-based nucleophiles in the presence of Pd(0)-catalysis was investigated. In all the cases studied, the reaction was totally regio- and diastereo-selective, affording a single adduct in moderate to good yields. Specifically, attack of the nucleophile at position 3 of the cyclopentene moiety, anti to the vicinal oxy group, with vinylogous ring opening of the aziridine ring, was observed. When the carbon acid is a very acidic methylene (pKa (DMSO) ≤ 7.3), the resulting adduct is a zwitterion, resulting from an intramolecular proton transfer between the amino group and the carbon acid moiety taking place after the C–C bond formation. A plausible mechanism for this transformation is put forward.
    Mots-clés : Bicyclic aziridine, Palladium catalysis, POLE 1, ROCS, Tsuji-trost reaction.

  • M. Roy, V. Berezhnaia, M. Villa, N. Vanthuyne, M. Giorgi, J. - V. Naubron, S. Poyer, V. Monnier, L. Charles, Y. Carissan, D. Hagebaum‐Reignier, J. Rodriguez, M. Gingras, et Y. Coquerel, « Stereoselective Syntheses, Structures, and Properties of Extremely Distorted Chiral Nanographenes Embedding Hextuple Helicenes », Angewandte Chemie International Edition, vol. 59, nᵒ 8, p. 3264-3271, 2020.
    Résumé : We report a molecular design and concept using π-system elongation and steric effects from helicenes surrounding a triphenylene core toward stable chiral polycyclic aromatic hydrocarbons (PAHs) with a maximal π-distortion to tackle their aromaticity, supramolecular and molecular properties. The selective syntheses, and the structural, conformational and chiroptical properties of two diastereomeric large multi-helicenes of formula C90H48 having a triphenylene core and embedding three [5]helicene units on their inner edges and three [7]helicene units at their periphery are reported based on diastereoselective and, when applicable, enantiospecific Yamamoto-type cyclotrimerizations of racemic or enantiopure 9,10-dibromo[7]helicene. Both molecules have an extremely distorted triphenylene core, and one of them exhibits the largest torsion angle recorded so far for a benzene ring (twist=36.9°).
    Mots-clés : aromaticity, helicenes, POLE 1, polycyclic aromatic hydrocarbons, ROCS, stereoselectivity, strained molecules.

  • R. Sala, F. Roudesly, L. F. Veiros, G. Broggini, J. Oble, et G. Poli, « Ru-Catalyzed Carbonylative Murai Reaction: Directed C3-Acylation of Biomass-Derived 2-Formyl Heteroaromatics », Advanced Synthesis & Catalysis, vol. 362, nᵒ 12, p. 2486-2493, 2020.
    Résumé : The Murai reaction is a ruthenium-catalyzed transformation leading to alkylated arenes through the C−C bond formation between an alkene and an arene bearing a directing group. Discovered in the nineties, this useful C−H activation based coupling has been the object of intense study since its discovery. After having studied the Murai reaction on 2-formylfurans of biomass derivation, we describe here the carbonylative version applied to 2-formylfurans, 2-formylpyrrols and 2-formylthiophenes. This acylation reaction takes place regioselectively at C3 position of the heterocyclopentadienes thanks to the installation of removable imine directing groups. The transformation can be achieved by treating the two reaction partners with a catalytic amount of Ru3(CO)12, in toluene at 120–150 °C, after CO bubbling, at atmospheric pressure. DFT computations of the full catalytic cycle help in deciphering the mechanism of this transformation, and to rationalize the different behaviors depending on the nature of imine directing groups.
    Mots-clés : carbonylation, C−H activation, homogeneous catalysis, Murai reaction, POLE 1, ROCS, ruthenium.
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  • J. Lalande et G. Poli, « Dialogue entre thermodynamique et chimie organique : manipuler avec soin concepts et vocabulaire », L'Actualité Chimique, nᵒ 437, p. 9-11, 2019.

  • Y. Liu, J. Oble, et G. Poli, « Switchable selectivity in Pd-catalyzed [3 + 2] annulations of γ-oxy-2-cycloalkenones with 3-oxoglutarates: C–C/C–C vs C–C/O–C bond formation », Beilstein Journal of Organic Chemistry, vol. 15, nᵒ 1, p. 1107-1115, mai 2019.
    Résumé : Beilstein Journal of Organic Chemistry
    Mots-clés : POLE 1, ROCS.
    Pièce jointe Full Text PDF 559.7 ko (source)

  • L. Luconi, G. Tuci, D. Yakhvarov, G. Poli, A. Rossin, A. Khusnuriyalova, et G. Giambastiani, « Imidazole-Bridged Tetrameric Group(IV) Heteroleptic Complexes from the Spontaneous Metal-Ligand Assembly of a Potentially N4-Tetradentate Ligand », European Journal of Inorganic Chemistry, vol. 2019, nᵒ 39-40, p. 4384-4393, oct. 2019.
    Résumé : The imidazole-containing N4-tetradentate ligand N-(2-(1H-imidazol-2-yl)-3-(pyridin-2-yl)propyl)-2,6-diisopropylaniline (L2H) and its N-benzyl-protected variant (L2Bn) at the imidazole fragment have been synthesized and fully characterized. Both molecules contain an unresolved Csp3 stereogenic center. The coordination behavior of the newly prepared ligands towards group IV metal ions (MIV = Zr, Hf) has been examined through multinuclear 1H and 13C{1H} NMR spectroscopy and selected single-crystal X-ray structural analyses. The ability of the imidazole fragment to enter the metal coordination sphere as a neutral or a monoanionic system has also been investigated, unveiling quite original coordination modes as well as unexpected molecular architectures. When one N imidazole atom is blocked by a benzyl protecting group (L2Bn), the ligand reaction with MIV(NMe2)4 (MIV = Zr, Hf) as metal precursor gives rise to discrete monometallic tris(dimethylamido) 5-coordinated compounds of general formula L2BnM(NMe2)3. The ligand chelates the metal ion as a bidentate monoanionic ?2{N?,N} system through the imidazole moiety and the anilido N donor while an uncoordinated picolyl arm dangles away from the metal center. Upon coordination to the metal ion, the unprotected L2H undergoes a unique self-assembly of the chiral racemic ligand to generate an achiral tetrameric network featuring a regularly alternating (R*,S*,R*,S*) configuration around the 6-coordinated metal centers. The resulting bis(dimethylamido) tetrameric architectures of formula [L2HM(NMe2)2]4 named ?poker complexes? contain the imidazole fragment of each ligand bridging two adjacent MIV ions in a µ-?{N}:?{N?} coordination hapticity. At the same time, the picolyl fragments of each chelating L2H ligand ?sting? a neighboring metal center as unconventional scorpion's tails that impose further rigidity to the tetrameric structure.
    Mots-clés : Hafnium, Imidazole, N ligands, POLE 1, ROCS, S4 symmetry, Supramolecular assembly, Zirconium.
    Note Note
    <p>doi: 10.1002/ejic.201900763</p>

  • J. M. J. M. Ravasco, C. M. Monteiro, F. Siopa, A. F. Trindade, J. Oble, G. Poli, S. P. Simeonov, et C. A. M. Afonso, « Creating Diversity from Biomass: A Tandem Bio/Metal-Catalysis towards Chemoselective Synthesis of Densely Substituted Furans », ChemSusChem, vol. 12, nᵒ 20, p. 4629-4635, 2019.
    Résumé : A new chemoselective (enzymatic desymmetrization/Ru-catalyzed C−H activation) sequence to obtain differently substituted furans from the largely available 2,5-furandicarboxylic acid (FDCA) was developed. Series of di- and trisubstituted furans were prepared in very good yields and excellent chemoselectivity. This study discloses a new approach towards valorization of the furanics platform through the use of FDCA as a stable intermediate, thus circumventing the chemical instability of the parent 5-hydroxymethylfurfural.
    Mots-clés : POLE 1, ROCS.
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  • V. N. Bochatay, F. Chemla, F. Ferreira, O. Jackowski, et A. Pérez-Luna, « β‐Amino Propargylic Fluorides through Stereoselective Electrophilic Fluorodesilylation of 4‐Amino‐1‐allenylsilanes - Bochatay - 2018 - European Journal of Organic Chemistry - Wiley Online Library », European Journal of Organic Chemistry, p. 3862, 2018.

  • K. de la Vega-Hernández, E. Romain, A. Coffinet, K. Bijouard, G. Gontard, F. Chemla, F. Ferreira, O. Jackowski, et A. Perez-Luna, « Radical Germylzincation of α-Heteroatom-Substituted Alkynes », Journal of the American Chemical Society, vol. 140, nᵒ 50, p. 17632-17642, déc. 2018.
    Résumé : The regio- and stereoselective addition of germanium and zinc across the C–C triple bond of nitrogen-, sulfur-, oxygen-, and phosphorus-substituted terminal and internal alkynes is achieved by reaction with a combination of R3GeH and Et2Zn. Diagnostic experiments support a radical-chain mechanism and the β-zincated vinylgermanes that show exceptional stability are characterized by NMR spectroscopy and X-ray crystallography. The unique feature of this new radical germylzincation reaction is that the C(sp2)–Zn bond formed remains available for subsequent in situ Cu(I)- or Pd(0)-mediated C–C or C–heteroatom bond formation with retention of the double bond geometry. These protocols offer modular access to elaborated tri- and tetrasubstituted vinylgermanes decorated with heteroatom substituents β to germanium that are useful for the preparation of stereodefined alkenes.
    Mots-clés : POLE 1, ROCS.

  • Y. Liu, Z. Mao, A. Pradal, P. - Q. Huang, J. Oble, et G. Poli, « Palladium-Catalyzed [3 + 2]-C–C/N–C Bond-Forming Annulation », Organic Letters, vol. 20, nᵒ 13, p. 4057-4061, juill. 2018.
    Résumé : The synthesis of bi- and tricyclic structures incorporating pyrrolidone rings is disclosed, starting from resonance-stabilized acetamides and cyclic α,β-unsaturated-γ-oxycarbonyl derivatives. This process involves an intermolecular Tsuji–Trost allylation/intramolecular nitrogen 1,4-addition sequence. Crucial for the success of this bis-nucleophile/bis-electrophile [3 + 2] annulation is its well-defined step chronology in combination with the total chemoselectivity of the former step. When the newly formed annulation product carries a properly located o-haloaryl moiety at the nitrogen substituent, a further intramolecular keto α-arylation can join the cascade, thereby forming two new cycles and three new bonds in the same synthetic operation.
    Mots-clés : POLE 1, ROCS.
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  • R. Maazaoui, R. Abderrahim, F. Chemla, F. Ferreira, A. Perez-Luna, et O. Jackowski, « Catalytic Chemoselective and Stereoselective Semihydrogenation of Alkynes to E-Alkenes Using the Combination of Pd Catalyst and ZnI2 », Organic Letters, vol. 20, nᵒ 23, p. 7544-7549, déc. 2018.
    Résumé : An efficient E-selective semihydrogenation of internal alkynes was developed under low dihydrogen pressure and low reaction temperature from commercially available reagents: Cl2Pd(PPh3)2, Zn0, and ZnI2. Kinetic studies and control experiments underline the significant role of ZnI2 in this process under H2 atmosphere, establishing that the transformation involves syn-hydrogenation followed by isomerization. This simple and easy-to-handle system provides a route to E-alkenes under mild conditions.
    Mots-clés : POLE 1, ROCS.

  • R. K. Nandi, A. Perez‐Luna, D. Gori, R. Beaud, R. Guillot, C. Kouklovsky, V. Gandon, et G. Vincent, « Triflic Acid as an Efficient Brønsted Acid Promoter for the Umpolung of N‐Ac Indoles in Hydroarylation Reactions », Advanced Synthesis & Catalysis, vol. 360, nᵒ 1, p. 161-172, janv. 2018.

  • F. Roudesly, L. F. Veiros, J. Oble, et G. Poli, « Pd-Catalyzed Direct C–H Alkenylation and Allylation of Azine N-Oxides », Organic Letters, vol. 20, nᵒ 8, p. 2346-2350, avr. 2018.
    Résumé : A Pd-catalyzed direct C2-alkenylation of azine N-oxides with allyl acetate is disclosed. The products are formed through an allylation/isomerization cascade process. The use of a tri-tert-butylphosphonium salt as the ligand precursor and KF is mandatory for optimal yields. When cinnamyl acetate is used, the same catalytic system promotes C2-cinnamylation of the azine N-oxide without subsequent isomerization. A mechanism is proposed on the basis of experimental studies and DFT calculations.
    Mots-clés : POLE 1, ROCS.

  • F. Siopa, V. - A. R. Cladera, C. A. M. Afonso, J. Oble, et G. Poli, « Ruthenium-Catalyzed C-H Arylation and Alkenylation of Furfural Imines with Boronates », European Journal of Organic Chemistry, vol. 2018, nᵒ 44, p. 6101-6106, 2018.
    Résumé : A Ru0-catalyzed direct C-H arylation and alkenylation of furfural imines with aryl- or alkenyl-boronates, in the presence of benzylideneacetone as a sacrificial hydride acceptor, is disclosed. This reaction provides access, after hydrolysis, to C3-arylated or vinylated furfural derivatives, and thus valorizes these relevant building-blocks obtained from lignocellulosic biomass. This approach, involving C-H activation by a Ru0/RuII, cycle offers several advantages, notably simple, mild and neutral reaction conditions.
    Mots-clés : Boronate derivatives, C-H activation, Furfurals, Imines, POLE 1, ROCS, Ruthenium.


  • R. Beaud, R. K. Nandi, A. Perez-Luna, R. Guillot, D. Gori, C. Kouklovsky, N. - E. Ghermani, V. Gandon, et G. Vincent, « Revealing the electrophilicity of N-Ac indoles with FeCl3: a mechanistic study », Chemical Communications, vol. 53, nᵒ 43, p. 5834-5837, mai 2017.
    Résumé : Herein, we report a mechanistic exploration of the unusual FeCl3-mediated hydroarylation of N-Ac indoles. Electron density topology analysis of a crystal, in situ IR monitoring, Hammett and Taft studies as well as DFT computations allowed us to determine that activation of acetyl with FeCl3 and of the C2C3 bond with a proton is involved.
    Mots-clés : POLE 1, ROCS.

  • M. Beaupérin, D. Polat, F. Roudesly, S. Top, A. Vessières, J. Oble, G. Jaouen, et G. Poli, « Approach to ferrocenyl-podophyllotoxin analogs and their evaluation as anti-tumor agents », Journal of Organometallic Chemistry, vol. 839, p. 83-90, juin 2017.
    Résumé : Podophyllotoxin is a natural product endowed of a high antimitotic activity and a high affinity for tubulin. Its action results in the cessation of cell division, inducing cell death. However, its high toxicity restrains its use as drug. To overcome this drawback, several chemical modifications of the native podophyllotoxin have been made. However, to date, no reports have so far been directed toward incorporation of a metallocene moiety. The search for new organometallic drugs is a central field in drug discovery, including the domain of cancer therapy. In particular, metallocenyl moieties are known to increase or decrease, depending on the degree of conjugation in the organometallic motif, the selectivity of drugs toward cancer cells. The conjugate organometallic compound reduces the damage of healthy tissues, yet permitting the selective desired antimitotic and cytotoxic effects

    of the active principle. We report here the synthesis of ferrocene-containing podophyllotoxin analogs and preliminary antiproliferative tests.
    Mots-clés : Antitumor agent, Bioorganometallic chemistry, CHEMBIO, Ferrocene, Multi-step synthesis, Palladium, Podophyllotoxin, POLE 1, POLE 3, ROCS.

  • V. N. Bochatay, L. Debien, F. Chemla, F. Ferreira, O. Jackowski, et A. Perez-Luna, « Synthesis of allenylzinc reagents by 1,2-rearrangement of alkynyl(disilyl)zincates derived from acetylenic epoxides and acetylenic aziridines », Comptes Rendus Chimie, vol. 20, nᵒ 6, p. 609-616, juin 2017.
    Résumé : Lithium alkynyl(disilyl)zincates obtained from metalated ethynyloxiranes, as well as from N-tert-butanesulfinyl(ethynyl)aziridines or N-tert-butanesulfonyl(ethynyl)aziridines, undergo 1,2-migration of the organosilyl group with ring opening of the oxirane or aziridine ring by SNi displacement. A developed protocol that involves nBuLi for the metalation step offers a straightforward approach to the corresponding δ-oxy- and δ-amino α-silyl allenylzinc intermediates. The reagents derived from the epoxides are amenable to subsequent in situ condensation with aldehydes or ketones to provide 1,3-diols but not those derived from aziridines that only react sluggishly in similar condensations.
    Mots-clés : alkynes, carbenoids, POLE 1, rearrangement, ROCS, silicon, Zinc.

  • T. Borelli, S. Brenna, G. Broggini, J. Oble, et G. Poli, « (Diacyloxyiodo)benzenes-Driven Palladium-Catalyzed Cyclizations of Unsaturated N-Sulfonylamides: Opportunities of Path Selection », Advanced Synthesis & Catalysis, vol. 359, nᵒ 4, p. 623-628, 2017.
    Résumé : A study of the palladium(II)-catalyzed cyclization of unsaturated N-sulfonylamides was undertaken, using (diacyloxyiodo)benzenes as terminal oxidizing agents. Different reactivities were observed as a function of the nature of the unsaturation (terminal vs. internal), or of the hypervalent iodine compound used (diacetoxyiodobenzene vs. bistrifluoroacetoxyiodobenzene). Proper parameter selection allows the direction of the cyclization to be chosen towards either a global aminoacetoxylation, an allylic amination via aminopalladation, or an allylic amination via allylic C–H activation.
    Mots-clés : allylic compounds, amination, C–H activation, homogeneous catalysis, Palladium, POLE 1, ROCS.

  • G. Bouhalleb, O. Mhasni, G. Poli, et F. Rezgui, « Direct palladium-catalyzed allylic alkylations of alcohols with enamines: Synthesis of homoallyl ketones », Tetrahedron Letters, vol. 58, p. 2525-2529, 2017.
    Résumé : An efficient, direct nucleophilic allylic substitution of α-, β- and γ-substituted alcohols with enamines, using the Pd(OAc)2/PPh3 catalyst system and ZnBr2 as a promoter in CH2Cl2 at reflux, is reported. The reaction course was dependent on the steric hindrance at the α- or γ-positions with respect to the functionalized α-carbon, selectively affording in moderate to good yields, α- or γ-homoallyl ketones, the so-called “linear” and “branched” products, respectively.
    Mots-clés : Allylic alcohol, Allylic substitution, Enamine, Homoallyl ketone, Palladium, POLE 1, ROCS.

  • C. Fopp, K. Isaac, E. Romain, F. Chemla, F. Ferreira, O. Jackowski, M. Oestreich, et A. Perez-Luna, « Stereodivergent Synthesis of β-Heteroatom-Substituted Vinyl­silanes by Sequential Silylzincation–Copper(I)-Mediated Electrophilic­ Substitution », Synthesis, vol. 49, nᵒ 04, p. 724-735, 2017.
    Résumé : Thieme E-Books & E-Journals
    Mots-clés : POLE 1, ROCS.

  • Z. Mao, E. Martini, G. Prestat, J. Oble, P. - Q. Huang, et G. Poli, « Analogues of the 2-carboxyl-6-hydroxyoctahydroindole (CHOI) unit from diverging Pd-catalyzed allylations: Selectivity as a function of the double bond position », Tetrahedron Letters, vol. 58, nᵒ 44, p. 4174-4178, nov. 2017.
    Résumé : Pd-catalyzed allylations of cyclic bis-allylic substrates, carried out either as two separate steps or in a pseudo-domino fashion, can generate 2-carboxyl-hexahydroindoles bearing an unsaturation in different positions. Sequential homologation, and epoxidation or syn-dihydroxylation steps were investigated to access analogues of the bicyclic 2-carboxyl-6-hydroxyoctahydroindole motif of aeruginosins, a family of peptides displaying serine protease inhibitor activity.
    Mots-clés : Allylic substitution, CHOI core, Domino reaction, Palladium catalysis, POLE 1, ROCS.

  • C. Pezzetta, L. F. Veiros, J. Oble, et G. Poli, « Murai Reaction on Furfural Derivatives Enabled by Removable N,N′-Bidentate Directing Groups », Chemistry - A European Journal, vol. 23, p. 8385-8389, 2017.
    Résumé : Furfural and related compounds are industrially relevant building blocks obtained from lignocellulosic biomass. To enhance the added value of these renewable resources, a Ru-catalyzed hydrofurylation of alkenes, involving a directed C−H activation at C3 of the furan ring, was developed. A thorough experimental study revealed that a bidentate amino-imine directing group enabled the desired coupling. Removal of the directing group occurred during the purification step, directly releasing the C3-functionalized furfurals. Development of the reaction as well as optimization and scope of the method were described. A mechanism was proposed on the basis of DFT calculations.
    Mots-clés : aldimines, alkenes, C−H activation, furfural, POLE 1, ROCS, Ruthenium.

  • A. Pontes da Costa, D. R. Nunes, M. Tharaud, J. Oble, G. Poli, et J. Rieger, « Palladium(0) Nanoparticles Embedded in Core–shell Nanogels as Recoverable Catalysts for the Mizoroki–Heck Reaction », ChemCatChem, vol. 9, nᵒ 12, p. 2167-2175, juin 2017.
    Résumé : Core–shell nanogels are attractive stabilizers and supports for catalytically active metallic nanoparticles. Herein, we present the synthesis and the characterization of a nanostructured well-defined core–shell nanogel with the ability to stabilize Pd0 nanoparticles in its core. This hybrid nanogel displays a remarkable stability in both the solid state and in solution. This feature allowed its successful application as a catalyst for the Mizoroki–Heck reaction between n-butyl acrylate and a series of bromo- and iodoarenes. The yields spanned from good to excellent, and catalyst recycling could be achieved up to three times without a significant activity loss. Three-phase tests indicated that the hybrid nanogel acts as a Pd0 nanoreservoir. The catalysis proceeds in a quasihomogeneous fashion as part of the catalytic activity occurs outside the nanogel, which explains the observed limited recyclability.
    Mots-clés : C−C coupling, immobilization, Palladium, POLE 1, POLE 4, POLYMERES, RAFT polymerization, ROCS, supported catalysts.
    Pièce jointe Full Text PDF 1.5 Mo (source)

  • I. Zelocualtecatl-Montiel, F. García-Álvarez, J. R. Juárez, L. Orea, D. Gnecco, A. Mendoza, F. Chemla, F. Ferreira, O. Jackowski, D. M. Aparicio, A. Perez-Luna, et J. L. Terán, « Asymmetric Tandem Conjugate Addition–Aldol Condensation with N-Acryloyloxazolidines Derived from 2-Phenylglycinol », Asian Journal of Organic Chemistry, vol. 6, nᵒ 1, p. 67-70, janv. 2017.
    Résumé : The tandem 1,4-addition–aldol condensation reaction of diethylzinc, α,β-unsaturated chiral enantiopure oxazolidines derived from 2-phenylglycinol, and carbonyl compounds is disclosed. The reaction proceeds through a radical-polar crossover mechanism involving the aldol condensation of a trisubstituted zinc enolate through a Zimmerman–Traxler transition state. Installation of a 2-pyridine moiety at the hemiaminal position of the chiral auxiliary allows obtaining both excellent asymmetric induction and diastereoselectivity (up to >90 % de). The developed protocol is suitable for aromatic and aliphatic aldehydes, as well as ketones.
    Mots-clés : aldol reaction, chiral oxazolidines, Diastereoselectivity, domino reactions, POLE 1, radical-polar mechanism, ROCS.


  • V. N. Bochatay, Z. Neouchy, F. Chemla, F. Ferreira, O. Jackowski, et A. Pérez-Luna, « 4-Amino-1-allenylsilanes from 4-Aminopropargylic Acetates through a Silylzincation/Elimination Sequence », Synthesis, vol. 48, nᵒ 19, p. 3287-3300, oct. 2016.
    Résumé : Thieme E-Books & E-Journals
    Mots-clés : POLE 1, ROCS.

  • D. Diamante, S. Gabrieli, T. Benincori, G. Broggini, J. Oble, et G. Poli, « Dehydrogenative Allylic Aminations of But-3-enoic Acid Derivatives », Synthesis, vol. 48, nᵒ 19, p. 3400-3412, oct. 2016.
    Résumé : Thieme E-Books & E-Journals
    Mots-clés : POLE 1, ROCS.

  • F. J. S. Duarte, G. Poli, et M. J. Calhorda, « Mechanistic Study of the Direct Intramolecular Allylic Amination Reaction Catalyzed by Palladium(II) », ACS Catalysis, vol. 6, nᵒ 3, p. 1772-1784, mars 2016.
    Résumé : DFT calculations (PBE1PBE/6-31G(d,p), Def2-TZVPPD) were performed to study the intramolecular C–H amination of an unsaturated carbamate catalyzed by [Pd(LL)(OAc)2] (2), where LL is the bis(sulfoxide) ligand PhS(O)(CH2)2S(O)Ph. The coordination takes place by an associative path over a trigonal-bipyramidal transition state. The LL ligand undergoes a coordination shift from κ2S,S to κ1S, leaving an open position for binding of the substrate (C═C). In the next step, the C–H activation, the transition state for the hydrogen abstraction from the substrate to form the σ-allyl complex has an energy of 124.0 kJ mol–1, which is the highest energy in the whole mechanism (TOF-determining transition state). The σ-allyl converts easily in the π-allyl, the acetic acid molecule leaving the coordination sphere. The remaining acetate receives the second hydrogen from the NH group, while the newly formed acetic acid molecule is replaced by the pendant arm of the LL ligand, and the cyclization takes place (nucleophilic attack). During these changes, the metal is reduced to Pd(0) in the form of the Pd(0) complex of the oxazolidinone product, the most stable species in the cycle (TOF-determining intermediate). Either the C–H activation or the Pd(0) oxidation may be the step determining the energy span of the reaction, depending on reaction conditions.
    Mots-clés : POLE 1, ROCS.

  • B. J. Fallon, V. Corcé, M. Amatore, C. Aubert, F. Chemla, F. Ferreira, A. Perez-Luna, et M. Petit, « A well-defined low-valent cobalt catalyst Co(PMe3)4 with dimethylzinc: a simple catalytic approach for the reductive dimerization of benzyl halides », New Journal of Chemistry, vol. 40, nᵒ 12, p. 9912-9916, nov. 2016.
    Résumé : Herein, we report the first catalytic version of a cobalt-catalysed reductive homocoupling of benzyl halides which proceeds with low catalyst loadings (0.5 to 5 mol%). By synthetizing each cobalt intermediate we demonstrate that reaction proceeds through two single electron transfers (SET) and that dimethylzinc is only involved in the regeneration of the catalytic species.
    Mots-clés : MACO, POLE 1, ROCS.

  • B. J. Fallon, E. Derat, M. Amatore, C. Aubert, F. Chemla, F. Ferreira, A. Perez-Luna, et M. Petit, « C2-Alkylation and Alkenylation of Indoles Catalyzed by a Low-Valent Cobalt Complex in the Absence of Reductant », Organic Letters, vol. 18, nᵒ 9, p. 2292-2295, 2016.
    Résumé : Herein an extremely versatile, well-defined, low-valent cobalt catalyst [Co(PMe3)4] capable of intermolecular and intramolecular imine-directed C2-alkylation and alkenylation of indoles is reported. The reaction proceeds in the absence of reducing agents or additives, affording a range of substituted indoles and dihydropyrroloindoles in high yields and regioselectivities. With the aid of deuterium labeling studies and DFT (Density Functional Theory) calculations, a mechanism is proposed that is based on a Ligand-to-Ligand Hydrogen Transfer pathway.
    Mots-clés : MACO, POLE 1, ROCS.

  • C. Fopp, E. Romain, K. Isaac, F. Chemla, F. Ferreira, O. Jackowski, M. Oestreich, et A. Perez-Luna, « Stereodivergent Silylzincation of α-Heteroatom-Substituted Alkynes », Organic Letters, vol. 18, nᵒ 9, p. 2054-2057, mai 2016.
    Résumé : Zinc reagents (Me2PhSi)2Zn and [(Me3Si)3Si]2Zn undergo highly regio- and stereoselective addition across the carbon–carbon triple bond of nitrogen-, sulfur-, oxygen-, and phosphorus-substituted terminal alkynes in the absence of copper or any other catalyst. Both reagents yield exclusively β-isomers, and the stereoselectivity is determined by the silyl group: Me2PhSi for cis or (Me3Si)3Si for trans. These stereodivergent silylzincation protocols offer an efficient access to heteroatom-substituted vinylsilanes with either double bond geometry, including trisubst

    ituted vinylsilanes by one-pot electrophilic substitution of the intermediate C(sp2)–Zn bond by copper(I)-mediated carbon–carbon bond formation.
    Mots-clés : POLE 1, ROCS.

  • D. Lebœuf, L. Marin, B. Michelet, A. Perez-Luna, R. Guillot, E. Schulz, et V. Gandon, « Harnessing the Lewis Acidity of HFIP through its Cooperation with a Calcium(II) Salt: Application to the Aza-Piancatelli Reaction », Chemistry - A European Journal, vol. 22, nᵒ 45, p. 16165-16171, nov. 2016.
    Résumé : A method to extend the scope of the aza-Piancatelli reaction between 2-furylcarbinols and anilines is depicted. We found that 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) is the solvent of choice for this transformation, as it outcompetes the usual solvents in terms of rate and yield. Side reactions and other issues raised by the title reaction are prevented, thereby providing an avenue to complex molecules that were previously inaccessible. Lewis acidity studies and computations were carried out to unveil the role of HFIP. Based on these results, we propose that HFIP is, in fact, acting as a Lewis acid and that its acidity can be enhanced when combined with a calcium(II) salt.
    Mots-clés : alcohol, Calcium, cooperative catalysis, Density functional calculations, electrocyclic reactions, POLE 1, ROCS.

  • M. M. Lorion, F. J. S. Duarte, M. J. Calhorda, J. Oble, et G. Poli, « Opening the Way to Catalytic Aminopalladation/Proxicyclic Dehydropalladation: Access to Methylidene γ-Lactams », Organic Letters, vol. 18, nᵒ 5, p. 1020-1023, mars 2016.
    Résumé : A new aerobic intramolecular palladium(II)-based catalytic system that triggers aminopalladation/dehydropalladation of N-sulfonylalkenylamides to give the corresponding methylidene γ-lactams has been identified. Use of triphenylphosphine and chloride anion as ligands is mandatory for optimal yields, and molecular oxygen can be used as the sole terminal oxidant. Scope and limitations of the methods are described. A mechanism is proposed on the basis of experimental results as well as density functional theory calculations.
    Mots-clés : POLE 1, ROCS.

  • M. M. Lorion, C. Kammerer, G. Prestat, et G. Poli, « Sequential Pd-catalyzed allylic alkylation / Ru-catalyzed ring-closing metathesis, », in Comprehensive Organic Chemistry Experiments for the Laboratory Classroom, C. A. M. Afonso, N. R. Candeias, D. P. Simao, A. F. Trindade, J. A. S. Coelho, et B. Tan, Éd. Royal Society of Chemistry Press, 2016, p. 650-655.
    Résumé : This expansive and practical textbook contains organic chemistry experiments for teaching in the laboratory at the undergraduate level covering a range of functional group transformations and key organic reactions.The editorial team have collected contributions from around the world and standardized them for publication. Each experiment will explore a modern chemistry scenario, such as: sustainable chemistry; application in the pharmaceutical industry; catalysis and material sciences, to name a few. All the experiments will be complemented with a set of questions to challenge the students and a section for the instructors, concerning the results obtained and advice on getting the best outcome from the experiment. A section covering practical aspects with tips and advice for the instructors, together with the results obtained in the laboratory by students, has been compiled for each experiment.Targeted at professors and lecturers in chemistry, this useful text will provide up to date experiments putting the science into context for the students.
    Mots-clés : POLE 1, ROCS.

  • M. M. Lorion, J. Oble, et G. Poli, « Palladium catalyzed oxidative aminations and oxylations: where are we? », Pure and Applied Chemistry, vol. 88, nᵒ 4, p. 381–389, janv. 2016.
    Résumé : Selective product formation in the Pd-catalyzed cyclization of unsaturated amide and carboxylic acid derivatives is an intriguing and challenging task. We recently discovered that the oxidative intramo-lecular Pd(II)-catalyzed amination or oxylation of unsaturated N-sulfonyl carbamates, N-sulfonyl carbox-amides and carboxylic acids takes place through the involvement of cyclic (usually, 5-or 6-membered) aminopalladated (AmPIs) or oxypalladated (OxPI) intermediates. Such cyclic intermediates can undergo a variety of transformations such as distocyclic β-H elimination, oxidative acetoxylation or intramolecular car-bopalladation, depending upon the substrate and/or the reaction conditions. In the absence of appropriate reaction pathways, the cyclic nucleopalladated intermediates (NuPIs) simply engage in an inconsequential equilibrium with the initial substrate and other transformations occur such as allylic C–H activation or, in the particular case of allyl carbamates, [3,3]-sigmatropic rearrangement.
    Mots-clés : POLE 1, ROCS.
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