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Tetsuya Takeya - One of the best experts on this subject based on the ideXlab platform.
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The aryl–aryl Coupling reaction of 1-naphthol with SnCl 4 for 2,2′-binaphthol synthesis and its application to the biomimetic synthesis of binaphthoquinone isolated from Plumbago zeylanica
Tetrahedron Letters, 2001Co-Authors: Iwao Okamoto, Eiichi Kotani, Hirohisa Doi, Tetsuya TakeyaAbstract:Abstract A simple method for the direct synthesis of 2,2′-binaphthols was developed, utilizing aryl–aryl Coupling reaction via electron donor–acceptor complexes of 1-naphthols with SnCl 4 . Heating of the complex in a sealed tube afforded the corresponding o - o Coupling product in excellent yield. This method was utilized for a biomimetic synthesis of the binaphthoquinone, 3,3′-biplumbagin, isolated from Plumbago zeylanica .
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synthesis of dibenzocyclooctadiene lignans isoschizandrin and their stereoisomers utilizing the samarium barbier reaction
Chemical & Pharmaceutical Bulletin, 1994Co-Authors: Tetsuya Takeya, Akira Ohguchi, Seisho TobinagaAbstract:Several (±)-dibenzocyclooctadiene lignans, (±)-isoschizandrin (1a), 1b, 2a, and 2b, were synthesized by the samarium-Barbier reaction of the phenylpropenes 4 and the phenylacetone 5 to give the erythro- and threo-butanols 6 and 7, followed by oxidative Aryl-Aryl Coupling reaction of each butanol.
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Synthesis of (.+-.)-Dibenzocyclooctadiene Lignans, (.+-.)-Isoschizandrin, and Their Stereoisomers, Utilizing the Samarium-Barbier Reaction.
Chemical & Pharmaceutical Bulletin, 1994Co-Authors: Tetsuya Takeya, Akira Ohguchi, Seisho TobinagaAbstract:Several (±)-dibenzocyclooctadiene lignans, (±)-isoschizandrin (1a), 1b, 2a, and 2b, were synthesized by the samarium-Barbier reaction of the phenylpropenes 4 and the phenylacetone 5 to give the erythro- and threo-butanols 6 and 7, followed by oxidative Aryl-Aryl Coupling reaction of each butanol.
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Synthesis of (±)-Dibenzocyclooctadiene Lignans, (±)-Schizandrin, (±)-Gomisin A and Their Stereoisomers, Utilizing the Samarium-Grignard Reaction
CHEMICAL & PHARMACEUTICAL BULLETIN, 1994Co-Authors: Tetsuya Takeya, Akira Ohguchi, Yoshiaki Ara, Seisho TobinagaAbstract:Several (±)-dibenzocyclooctadiene lignans, (±)-schizandrin (1a) (±)-gomisin A (1b), and their stereoisomers 2a and 2b, were synthesized by the samarium-Grignard reaction of the phenylpropyl bromides 4 and the phenylacetone derivative 5 to give the erythro and threo-butanols 6 and 7 followed by oxidative Aryl-Aryl Coupling reaction of each butanol.
Marta Catellani - One of the best experts on this subject based on the ideXlab platform.
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formation of a carbonyl group ortho to a biaryl structure or a 6h dibenzopyran by a palladium norbornene catalyzed ordered reaction sequence
Tetrahedron, 2015Co-Authors: Nicola Della Ca, Mirko Cremaschi, Riccardo Lucentini, Marta Catellani, Marco Fontana, Di Xu, Zhiming Zhou, Elena MottiAbstract:Abstract Developments are reported in the catalytic synthesis of biaryls containing an ortho-carbaldehyde or 6H-dibenzopyrans in the presence of palladium/norbornene as catalyst. The reaction of o-substituted aryl iodides and o-bromobenzyl alcohols proceeds by unsymmetrical Aryl-Aryl Coupling to form a seven-membered oxapalladacycle intermediate, which may undergo an intramolecular redox process to form carbonyl groups or a C–O Coupling to six-membered cyclic ethers. The predominant formation of dibenzopyrans as well as of biaryl structures containing the oxidized CHO group in one ring and the reduced CH2OH in the other is described along with some mechanistic insights.
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Formation of a carbonyl group ortho to a biaryl structure or a 6H-dibenzopyran by a palladium/norbornene-catalyzed ordered reaction sequence
Tetrahedron, 2015Co-Authors: Nicola Della Ca, Mirko Cremaschi, Riccardo Lucentini, Marta Catellani, Marco Fontana, Zhiming Zhou, Elena MottiAbstract:Abstract Developments are reported in the catalytic synthesis of biaryls containing an ortho -carbaldehyde or 6 H -dibenzopyrans in the presence of palladium/norbornene as catalyst. The reaction of o -substituted aryl iodides and o -bromobenzyl alcohols proceeds by unsymmetrical Aryl-Aryl Coupling to form a seven-membered oxapalladacycle intermediate, which may undergo an intramolecular redox process to form carbonyl groups or a C–O Coupling to six-membered cyclic ethers. The predominant formation of dibenzopyrans as well as of biaryl structures containing the oxidized CHO group in one ring and the reduced CH 2 OH in the other is described along with some mechanistic insights.
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Of the Ortho Effect in Palladium/Norbornene-Catalyzed Reactions: A Theoretical Investigation
Journal of the American Chemical Society, 2011Co-Authors: Giovanni Maestri, Elena Motti, Nicola Della Ca, Max Malacria, Etienne Derat, Marta CatellaniAbstract:Mechanistic questions concerning palladium and norbornene catalyzed aryl–aryl Coupling reactions are treated in this paper: how aryl halides react with the intermediate palladacycles, formed by interaction of the two catalysts with an aryl halide, and what is the rational explanation of the “ortho effect” (caused by an ortho substituent in the starting aryl halide), which leads to aryl–aryl Coupling with a second molecule of aryl halide rather than to aryl–norbornyl Coupling. Two possible pathways have been proposed, one involving aryl halide oxidative addition to the palladacycle, the other passing through a palladium(II) transmetalation, also involving the palladacycle, as previously proposed by Cardenas and Echavarren. Our DFT calculations using M06 show that, in palladium-catalyzed reaction of aryl halides, not containing ortho substituents, and norbornene, the intermediate palladacycle formed has a good probability to undergo transmetalation, energetically favored over the oxidative addition leading ...
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A new type of palladium-catalysed aromatic cross-Coupling combined with a Suzuki reaction: synthesis of selectively 2,3′-substituted 1,1′;2′,1″-terphenyl derivatives
Journal of Molecular Catalysis A-chemical, 2003Co-Authors: Elena Motti, Antonella Mignozzi, Marta CatellaniAbstract:Abstract A one-pot catalytic synthesis of selectively substituted terphenyl derivatives is reported. The method is based on the combination of a new palladium- and norbornene-mediated aryl–aryl Coupling of two molecules of an ortho-substituted aryl iodide with a Suzuki-type arylation. Under the reported conditions, the reaction follows a precisely ordered sequence of steps and the Suzuki Coupling only occurs at the end of the sequence. While proposing a new pathway for CC Coupling, the process provides a simple and efficient tool for preparing an interesting class of ortho-substituted terphenyls catalytically and with satisfactory yields.
Jin-soo Seo - One of the best experts on this subject based on the ideXlab platform.
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A new vinyl ether type linker for solid-phase synthesis
Tetrahedron Letters, 2000Co-Authors: Sung-eun Yoo, Young-dae Gong, Min-young Choi, Jin-soo SeoAbstract:Abstract A new vinyl ether type of linker based on 4-hydroxy phenethyl alcohol is developed for the solid-phase synthesis as demonstrated in the Suzuki type of aryl–aryl Coupling reaction for the preparation of various biphenyl tetrazole derivatives.
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Solid phase synthesis of biphenyltetrazole derivatives
Tetrahedron Letters, 1997Co-Authors: Sung-eun Yoo, Jin-soo Seo, Young-dae GongAbstract:Abstract A dihydropyran carboxylic acid type linker is suitable for the solid phase Suzuki type Aryl-Aryl Coupling reaction for the preparation of various biphenyltetrazole derivatives.
Young-dae Gong - One of the best experts on this subject based on the ideXlab platform.
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A new vinyl ether type linker for solid-phase synthesis
Tetrahedron Letters, 2000Co-Authors: Sung-eun Yoo, Young-dae Gong, Min-young Choi, Jin-soo SeoAbstract:Abstract A new vinyl ether type of linker based on 4-hydroxy phenethyl alcohol is developed for the solid-phase synthesis as demonstrated in the Suzuki type of aryl–aryl Coupling reaction for the preparation of various biphenyl tetrazole derivatives.
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Solid phase synthesis of biphenyltetrazole derivatives
Tetrahedron Letters, 1997Co-Authors: Sung-eun Yoo, Jin-soo Seo, Young-dae GongAbstract:Abstract A dihydropyran carboxylic acid type linker is suitable for the solid phase Suzuki type Aryl-Aryl Coupling reaction for the preparation of various biphenyltetrazole derivatives.
Frédéric R. Leroux - One of the best experts on this subject based on the ideXlab platform.
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Control of axial chirality in absence of transition metals based on arynes
Comptes Rendus Chimie, 2017Co-Authors: Frédéric R. Leroux, Armen Panossian, David AugrosAbstract:The modular construction of enantioenriched biaryl derivatives is presented. This approach is based on (a) an almost quantitative access to polybrominated precursors via a transition metal-free Aryl-Aryl Coupling, the ARYNE-Coupling, (b) the regioselective introduction of a traceless chiral auxiliary (an enantiopure para-tolylsulfinyl group), (c) the chemoselective functionalization of this auxiliary and (d) subsequent regioselective functionalization of the remaining bromine atoms without any racemization during these steps. Next, the atropo-selective Coupling of in situ generated arynes and aryllithiums bearing various chiral auxiliaries (tert-butylsulfoxide, para-tolylsulfoxide, tartrate-derived chiral diethers and oxazolines) is described and applied to the formal synthesis of (-)-steganacin
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Lithium/Element Exchange as an Efficient Tool for Accessing Atropo-enriched Biaryls via Arynes.
Chimia, 2016Co-Authors: Armen Panossian, Frédéric R. LerouxAbstract:This account documents the development of transition metal-free, aryne-mediated Aryl-Aryl Coupling, the 'ARYNE Coupling', which began in 2001 in Lausanne. ortho,ortho'-Di-, tri- and even tetrasubstituted biphenyls have now become accessible on a multi-gram scale. The reaction is perfectly regioselective and the obtained polybromobiphenyls can be submitted to regioselective bromine/lithium interconversions. The access to enantiopure biphenyls is now possible using enantiopure sulfoxides as chiral auxiliaries, which allow for subsequent chemoselective sulfoxide/metal exchange on each atropo-diastereoisomer with configurational stability of the intermediate biaryllithiums. Direct atropo-diastereoselective ARYNE Coupling has been reported more recently.
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Atroposelective synthesis of axially chiral P,S-ligands based on arynes
Organic Chemistry Frontiers, 2015Co-Authors: Anais Berthelot-brehier, Armen Panossian, Françoise Colobert, Frédéric R. LerouxAbstract:The first atropo-selective aryl–aryl Coupling based on arynes in the presence of a tert-butylsulfinyl group as the chiral auxiliary on the aryllithium nucleophile is described. The approach allows for the efficient access to a novel family of atropo-enantiopure biphenyl-based phosphine–thioether ligands. The new P,S heterodonor ligands were assessed in model palladium-catalyzed allylic substitution reactions.
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Transition-metal-free atropo-selective synthesis of biaryl compounds based on arynes.
Chemistry (Weinheim an der Bergstrasse Germany), 2012Co-Authors: Frédéric R. Leroux, Armen Panossian, Anaïs Berthelot, Laurence Bonnafoux, Françoise ColobertAbstract:A modular way towards biaryls: Highly enantioenriched biphenyls can be prepared based on a transition-metal-free Aryl-Aryl Coupling followed by efficient desymmetrization or deracemization and chemoselective functionalization (see scheme).
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A Practical Transition Metal-Free Aryl-Aryl Coupling Method: Arynes as Key Intermediates
Advanced Synthesis & Catalysis, 2007Co-Authors: Frédéric R. Leroux, Laurence Bonnafoux, Françoise Colobert, Christophe Heiss, Don Antoine LanfranchiAbstract:Upon treatment of various aryllithium intermediates with 1,2-dibromobenzene or 1-bromo-2-iodobenzene, dissymmetrical ortho,ortho′-di-, tri- and even tetrasubstituted bromo- or iodobiaryls become readily available. The crucial steps in all these reactions were the nucleophilic addition of the organolithium precursor to a transient aryne species released from it by β-elimination of a lithium halide and, stabilization of the resulting 2-biaryllithium intermediate by in situ transfer of bromine or iodine from the starting material. This straightforward transition metal-free access to biaryls allows the preparation of highly valuable halobiaryls on a gram scale in excellent yields. These precursors can be subsequently functionalized by highly regioselective halogen/metal permutations into a vast variety of target molecules. This was demonstrated in the synthesis of several mono- and diphosphine ligands.
