- Probing delocalisation across highly ethynylated mono and dinuclear Pt(II) tethers containing nitrogroups and organic models as redox active probes: X-ray crystal structure of trans-[Pt(CC-C6H4NO2) 2(PPh3
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The electrochemical study on Pt(II) organometallic and organic ethynylated compounds bearing nitro substituents in the phenyl groups has been performed, demonstrating that the presence of severe chemical irreversibility accompanying the electron transfer,
- Ravera, Mauro,D'Amato, Rosaria,Guerri, Annalisa
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Read Online
- A new access to tri(1-naphthyl)phosphine and its catalytically active palladacycles and luminescent Cu(I) complex
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New approach to synthesis of tri(1-naphthyl)phosphine (Np3P) and its application for design of new Pd(II) and Cu(I) complexes are reported. This phosphine has been prepared in 32% yield through exhaustive P–H arylation of РН3 with 1-chloronaphthalene in the superbasic t-BuOK/DMSO system at 70 °C. The Np3P was found to readily reacts with chloro-bridged dimers, [(κ2-C,N)Pd(μ-Cl)]2 (κ2-C,N = PhCH2NMe2 (2a) or FcCH2NMe2 (2b), to give new mononuclear palladacycles [(κ2-C,N)Pd(Np3P)Cl] (3, 4), in which metal has a square-planar geometry. These complexes show good catalytic activity in the Sonogashira reaction under low catalyst loadings (2 mol% Pd) and relatively mild conditions. We also synthesized and characterized first Cu(I) complex with Np3P, namely, [Cu(phen)(Np3P)I], that exhibits red emission (λmax = 650 nm) at room temperature.
- Artem'ev, Alexander V.,Kuimov, Vladimir A.,Matveeva, Elena A.,Bagryanskaya, Irina Yu.,Govdi, Anastasia I.,Vasilevsky, Sergey F.,Rakhmanova, Mariana I.,Samultsev, Dmitry O.,Gusarova, Nina K.,Trofimov, Boris A.
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Read Online
- Selective Synthesis of Non-Aromatic Five-Membered Sulfur Heterocycles from Alkynes by using a Proton Acid/N-Chlorophthalimide System
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A multicomponent strategy to achieve two different regioselectivities from alkynes, isothiocyanates and H2O with a proton acid/N-chlorophthalimide (NCPI) system is described to selectively obtain non-aromatic five-membered sulfur heterocycles (1,3-oxathiol-2-imines/thiazol-2(3H)-one derivatives) through multiple bond formations. The process features readily available starting materials, mild reaction conditions, broad substrate scope, good functional-group tolerance, high regio- and chemo- selectivities, gram-scale synthesis and late-stage modifications. Mechanistic studies support the proposal that the transformation process includes a combination of H2O and isothiocyanate, free-radical formation, carbonation and intramolecular cyclization to give the products. Furthermore, the 1,3-oxathiol-2-imine derivatives possess unique fluorescence characteristics and can be used as Pd2+ sensors with a “turn-off” response, demonstrating potential applications in environmental and biological fields.
- Yu, Wentao,Zhu, Baiyao,Shi, Fuxing,Zhou, Peiqi,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 1313 - 1322
(2020/12/01)
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- Synthesis and Photophysical Study of Heteropolycyclic and Carbazole Motif: Nickel-Catalyzed Chelate-Assisted Cascade C-H Activations/Annulations
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Herein, nickel-catalyzed synthesis of polyarylcarbazole through sequential C-H bond activations has been described. Regioselective indole C2/C3 functionalization has been achieved in the presence of indole C7-H, which is quite challenging. In addition, this approach also gives easy access to building a heteropolycyclic motif through C6/C7 C-H functionalization of indoline. This methodology is not limited to aromatic internal alkynes as coupling partners; aliphatic alkynes have also shown good tolerance. Notably, during the optimization the catalytic enhancement with sodium iodide as an additive has been observed. We have also studied the photophysical properties of these highly conjugated molecules.
- Prusty, Namrata,Banjare, Shyam Kumar,Mohanty, Smruti Ranjan,Nanda, Tanmayee,Yadav, Komal,Ravikumar, Ponneri C.
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supporting information
p. 9041 - 9046
(2021/11/30)
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- Co3O4 nanoparticles embedded in triple-shelled graphitic carbon nitride (Co3O4/TSCN): a new sustainable and high-performance hierarchical catalyst for the Pd/Cu-free Sonogashira–Hagihara cross-coupling reaction
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Inspired by the synthesis of triple-shelled periodic mesoporous organosilica hollow spheres, a straightforward and controllable approach for the preparation of Co3O4 NPs embedded in triple-shelled graphitic carbon nitride has been es
- Ghodsinia, Sara S. E.,Akhlaghinia, Batool,Jahanshahi, Roya
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p. 3217 - 3244
(2021/05/17)
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- Iodonium Cation-Pool Electrolysis for the Three-Component Synthesis of 1,3-Oxazoles
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The synthesis of 1,3-oxazoles from symmetrical and unsymmetrical alkynes was realized by an iodonium cation-pool electrolysis of I2 in acetonitrile with a well-defined water content. Mechanistic investigations suggest that the alkyne reacts with the acetonitrile-stabilized I+ ions, followed by a Ritter-type reaction of the solvent to a nitrilium ion, which is then attacked by water. The ring closure to the 1,3-oxazoles released molecular iodine, which was visible by the naked eye. Also, some unsymmetrical internal alkynes were tested and a regioselective formation of a single isomer was determined by two-dimensional NMR experiments.
- Sattler, Lars E.,Hilt, Gerhard
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supporting information
p. 605 - 608
(2020/12/07)
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- Phenazine-Based Donor Acceptor Systems as Organic Photocatalysts for "metal-free" C-N/C-C Cross-Coupling
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With an aim to achieve a balance between ground-state and excited-state reduction potential of donor acceptor systems for efficient C-N/C-C cross-coupling, a series of donor acceptor systems DA1-DA4 have been synthesized by varying the donor strength and connecting positions. With an increase in donor strength, systematic elevation in the ground-state reduction potential and decrease in the HOMO-LUMO gap was observed. Interestingly, all the derivatives DA1-DA4 could catalyze the C-N bond formation reaction between activated aryl halides and amines at low catalytic loading under metal-free conditions without the need of any external base upon irradiation with white LED. A balance was realized in the case of derivative DA2, which exhibits high efficiency in C-N couplings. Different control experiments support the validity of the energy as well as electron transfer pathways in the visible light-mediated C-N bond formation. This study further reveals the potential of derivative DA1 in "metal-free"Sonogashira coupling involving activated aryl halides which is attributed to its high excited-state reduction potential.
- Deol, Harnimarta,Singh, Gurpreet,Kumar, Manoj,Bhalla, Vandana
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p. 11080 - 11093
(2020/10/12)
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- Sequentially Pd/Cu-Catalyzed Alkynylation-Oxidation Synthesis of 1,2-Diketones and Consecutive One-Pot Generation of Quinoxalines
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We report a simple and efficient one-pot synthesis of 1,2-diketones by concatenation of two Pd/Cu-catalyzed processes: Pd0/CuI-catalyzed Sonogashira coupling of terminal alkynes with aryl (pseudo)halides furnishes internal alkynes, which are directly transformed by PdII/CuII-catalyzed Wacker-type oxidation with DMSO and oxygen as dual oxidants to furnish 1,2-diketones. With this efficient, catalyst economical process, various aryl iodides and triflates are efficiently transformed in high yields into symmetrically and unsymmetrically substituted 1,2-diketones with various functional groups. This process can be readily extended to a consecutive one-pot synthesis of quinoxalines in a diversity-oriented fashion.
- Niesobski, Patrik,Martínez, Ivette Santana,Kustosz, Sebastian,Müller, Thomas J. J.
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supporting information
p. 5214 - 5218
(2019/07/31)
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- Rate Enhancement in CAN-Promoted Pd(PPh3)2Cl2-Catalyzed Oxidative Cyclization: Synthesis of 2-Ketofuran-4-carboxylate Esters
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Stoichiometric ceric ammonium nitrate (CAN) and a catalytic amount of Pd(PPh3)2Cl2 (5 mol %) can rapidly produce multisubstituted 2-ketofuran-4-carboxylate esters from 2-propargylic 1,3-ketoesters via oxidative O-cyclization reaction. Pd(PPh3)2Cl2 was found to be the crucial catalyst as its inclusion greatly enhanced the rate of the reaction and cleanly afforded the products within minutes. Over 30 substrates were successfully converted to the desired compounds in mostly moderate to good yields.
- Ruengsangtongkul, Sureeporn,Chaisan, Nattawadee,Thongsornkleeb, Charnsak,Tummatorn, Jumreang,Ruchirawat, Somsak
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supporting information
p. 2514 - 2517
(2019/04/30)
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- Pd-Catalyzed Alkyne Insertion/C-H Activation/[4 + 2] Carboannulation of Alkenes to the Synthesis of Polycyclics
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An unprecedented Pd-catalyzed alkyne insertion/C-H activation/intramolecular [4 + 2] carboannulation of alkenes has been reported. In this transformation, the C-H activation was triggered by an in situ generated alkenylpalladium species via the Pd-catalyzed cross-coupling reaction of aryl iodides and alkynes. Subsequently, the resulting five-membered C, C-palladacycle intermediates were added across the alkenes, providing a unique approach to access diversified polycyclics in good efficiency. Two new rings and three C-C bonds were formed in one pot.
- Guo, Songjin,Li, Panpan,Guan, Zhe,Cai, Libo,Chen, Siwei,Lin, Aijun,Yao, Hequan
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supporting information
p. 921 - 925
(2019/05/16)
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- One-Pot Domino Synthesis of Diarylalkynes/1,4-Diaryl-1,3-diynes by [9,9-Dimethyl-4,5-bis(diphenylphosphino)xanthene] (Xantphos)–Copper(I) Iodide–Palladium(II) Acetate-Catalyzed Double Sonogashira-Type Reaction
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The low loading combination of the complex [9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene] (Xantphos)copper(I) iodide and simple ligand-free palladium(II) acetate was found to be efficient for the domino synthesis of diarylalkynes by the reaction of aryl halides with trimethylsilylethynylene or bis(trimethylsilyl)acetylene in a single-step procedure. The unsymmetrical diarylalkynes can be obtained through a one-pot two-step approach. The reactions of aryl bromides with 1,4-bis(trimethylsilyl)butadiyne also furnished the corresponding 1,4-diaryl-1,3-diynes in a similar fashion. This route to diarylalkynes and 1,4-diaryl-1,3-diynes is complementary to previously reported synthetic procedures. (Figure presented.).
- Qiu, Shaozhong,Zhang, Caiyang,Qiu, Rui,Yin, Guodong,Huang, Jinkun
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p. 313 - 321
(2018/01/15)
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- A Sustainable, User-Friendly Protocol for the Pd-Free Sonogashira Coupling Reaction
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We herein present a new catalytic system for the palladium-free Sonogashira coupling reaction. The catalytically active moiety is formed in situ, in a straightforward and user-friendly manner, by combining a widely available low-cost copper salt and an N-
- Liori, Aggeliki A.,Stamatopoulos, Ioannis K.,Papastavrou, Argyro T.,Pinaka, Afroditi,Vougioukalakis, Georgios C.
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p. 6134 - 6139
(2018/09/06)
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- Tri(1-naphthyl)phosphine as a ligand in palladium-free Sonogashira cross-coupling of arylhalogenides with acetylenes
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Tri(1-naphthyl)phosphine (Np3P) has been easily prepared in 34% yield from red phosphorus and 1-bromonaphthalene in the superbasic system t-BuONa/DMSO. The expedient procedures for the synthesis of aryl acetylenes by Sonogashira coupling of aryl iodides with terminal alkynes using Np3P as a ligand have been developed. For the first time, it is found that the reaction with compounds containing electron-donating substituents preferably affords buta-1,3-diynes.
- Govdi, Anastasiya I.,Vasilevsky, Sergey F.,Malysheva, Svetlana F.,Kazheva, Olga N.,Dyachenko, Oleg A.,Kuimov, Vladimir A.
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- Preparation method of diaryl acetylene compounds
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The invention relates to preparation of an organic compound, and aims to provide a preparation method of diaryl acetylene compounds. The preparation method includes steps of adding associated tribromomethylarene compound and copper in a reactor to perform deoxidizing treatment; dissolving polyamine in a proper amount of anhydrous and oxygen-free solvent, and then adding to the reactor; performingcoupling reaction at 30-80DEG C for 3-12 hours; separating and purifying to obtain diaryl acetylene compounds. The preparation is gentle in synthesis condition and the reaction has good compatibilityto different functional groups; the raw material associated tribromomethylarene compound is convenient to compound and has different substituent groups and variable structure; by adopting one raw material, high-quality product can be obtained through simple treatment, and the output is high; by adopting two different raw materials, the asymmetrical diaryl acetylene compound can be prepared.
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Page/Page column 0076; 0077; 0078; 0094; 0113
(2018/05/16)
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- Cp?CoIII-Catalyzed Synthesis of Pyrido[2′,1′:2,3]pyrimido[1,6-a]indol-5-iums via Tandem C-H Activation and Subsequent Annulation from 1-(Pyridin-2-yl)-1H-indoles and Internal Alkynes
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A Cp?CoIII-catalyzed C2-selective C-H alkenylation/annulation cascade transformation of 1-(pyridin-2-yl)-1H-indoles with internal alkynes to afford pyrido[2′,1′:2,3]pyrimido[1,6-a]indol-5-iums is presented. Moreover, 6,7-dihydro-4H-pyrido[2′,1′:2,3]pyrimido[1,6-a]indole, a new functionalized N-fused indole core heterocycle, could be constructed effectively via reduction of pyrido[2′,1′:2,3]pyrimido[1,6-a]indol-5-ium by NaBH4.
- Yang, Yuhan,Li, Bo,Liu, Wenmin,Zhang, Rumeng,Yu, Lintao,Ma, Qin-Ge,Lv, Rongrong,Du, Donghua,Li, Ting
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p. 11335 - 11345
(2016/11/29)
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- Highly Active Multidentate Ligand-Based Alkyne Metathesis Catalysts
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Alkyne metathesis catalysts composed of molybdenum(VI) propylidyne and multidentate tris(2-hydroxylbenzyl)methane ligands have been developed, which exhibit excellent stability (remains active in solution for months at room temperature), high activity, an
- Du, Ya,Yang, Haishen,Zhu, Chengpu,Ortiz, Michael,Okochi, Kenji D.,Shoemaker, Richard,Jin, Yinghua,Zhang, Wei
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supporting information
p. 7959 - 7963
(2016/06/09)
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- Reaction of elemental phosphorus with α-methylstyrenes: One-pot synthesis of secondary and tertiary phosphines, prospective bulky ligands for Pd(II) catalysts
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α-Methylstyrene and 4-chloro-α-methylstyrene react readily with elemental (red) phosphorus under microwave-irradiation in the superbase KOH/DMSO suspension to afford, depending on the reactant ratio and reaction time, either corresponding bis(2-arylpropyl
- Artem'ev, Alexander V.,Malysheva, Svetlana F.,Gusarova, Nina K.,Belogorlova, Nataliya A.,Sukhov, Boris G.,Sutyrina, Anastasiya O.,Matveeva, Elena A.,Vasilevsky, Sergey F.,Govdi, Anastasiya I.,Gatilov, Yuriy V.,Albanov, Alexander I.,Trofimov, Boris A.
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p. 443 - 450
(2015/12/31)
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- Catalysts for the alkyne metathesis
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Organometallic compounds of the general formula (I), in which M=Mo, W, are claimed.
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Page/Page column 22; 23; 24; 38; 39
(2015/04/15)
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- Palladium nanoparticles catalyzed Sonogashira reactions for the one-pot synthesis of symmetrical and unsymmetrical diarylacetylenes
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A variety of symmetrical and unsymmetrical diarylacetylenes are synthesized by ligand-free palladium nanoparticles catalyzed copper-free and amine-free Sonogashira cross-coupling reactions between aryl iodides and trimethylsilylacetylene (TMSA) under mild reaction conditions.
- Mandali, Pavan Kumar,Chand, Dillip Kumar
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- 2,5-Bis(2-(diphenylphosphino)phenyl)-1,3,4-oxadiazole ligands and their Cu(I) complexes for Sonogashira coupling reaction
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Two diphosphane ligands - 2,5-bis(2-(diphenylphosphino)-5-R)phenyl)-1,3,4- oxadiazole (L1, R = H, L2, R = OMe) and their binuclear complexes, L1Cu and L2Cu, were prepared and characterized. The molecular structures of L1Cu and L2Cu, as perchlorate salts,
- Lin, Cai-Xia,Zhu, Jia-Fang,Li, Qing-Shan,Ao, Li-Hua,Jin, Yan-Juan,Xu, Feng-Bo,Hu, Fang-Zhong,Yuan, Yao-Feng
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p. 298 - 303
(2014/04/03)
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- Palladium-catalyzed oxidative annulation of acrylic acid and amide with alkynes: A practical route to synthesize α-pyrones and pyridones
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A range of internal alkynes smoothly underwent palladium-catalyzed oxidative annulations with acrylic acid and amide to afford α-pyrones and pyridones in good to excellent yields with high regioselectivity. The usage of O2 (1 atm) as a stoichiometric oxidant with H2O as the only byproduct under mild conditions makes this process more attractive and practical.
- Yu, Yue,Huang, Liangbin,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 2146 - 2149
(2014/05/06)
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- Tetraarylcyclobutadienecyclopentadienylcobalt complexes: Synthesis, electronic spectra, magnetic circular dichroism, linear dichroism, and TD DFT calculations
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The known (tetraphenyl-η4-cyclobutadiene)- η5-cyclopentadienylcobalt (1) and a series of its new substituted derivatives have been prepared. The electronic states of a few representatives have been characterized by absorption and magnetic circular dichroism. Time-dependent density functional theory has been used to arrive at spectral assignments for several prominent low-energy bands. The absorption spectra of the radical ions of 1 have also been recorded.
- Kottas, Gregg S.,Brotin, Thierry,Schwab, Peter F. H.,Gala, Kamal,Havlas, Zdenek,Kirby, James P.,Miller, John R.,Michl, Josef
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p. 3251 - 3264
(2014/08/05)
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- Multidentate triphenolsilane-based alkyne metathesis catalysts
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A series of triphenolsilane-coordinated molybdenum(VI) propylidyne catalysts has been developed, which are resistant to small alkyne polymerization and compatible with various functional groups (including phenol substrates). The catalysts remain active in
- Yang, Haishen,Liu, Zhenning,Zhang, Wei
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supporting information
p. 885 - 890
(2013/05/08)
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- Highly Active Multidentate Catalysts for Efficient Alkyne Metathesis
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The invention relates to highly active and selective catalysts for alkyne metathesis. In one aspect, the invention includes a multidentate organic ligand wherein one substrate-binding site of the metal center is blocked. In another aspect, the invention includes N-quaternized or silane-based multidentate organic ligands, capable of binding to metals. In yet another aspect, the invention includes N-quaternized or silane-based multidentate catalysts. The catalysts of the invention show high robustness, strong resistance to small alkyne polymerization and significantly enhanced catalytic activity compared to their corresponding non-quaternized or non-silane-based multidentate catalyst analogues.
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Paragraph 0281; 0282
(2013/10/08)
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- HCV NS5A replication complex inhibitors. Part 3
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In a recent disclosure,1 we described the discovery of dimeric, prolinamide-based NS5A replication complex inhibitors exhibiting excellent potency towards an HCV genotype 1b replicon. That disclosure dealt with the SAR exploration of the peripheral region of our lead chemotype, and herein is described the SAR uncovered from a complementary effort that focused on the central core region. From this effort, the contribution of the core region to the overall topology of the pharmacophore, primarily vector orientation and planarity, was determined, with a set of analogs exhibiting 50 in a genotype 1b replicon assay.
- Lopez, Omar D.,Nguyen, Van N.,St. Laurent, Denis R.,Belema, Makonen,Serrano-Wu, Michael H.,Goodrich, Jason T.,Yang, Fukang,Qiu, Yuping,Ripka, Amy S.,Nower, Peter T.,Valera, Lourdes,Liu, Mengping,O'Boyle II, Donald R.,Sun, Jin-Hua,Fridell, Robert A.,Lemm, Julie A.,Gao, Min,Good, Andrew C.,Meanwell, Nicholas A.,Snyder, Lawrence B.
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p. 779 - 784
(2013/02/25)
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- Optimized synthesis, structural investigations, ligand tuning and synthetic evaluation of silyloxy-based alkyne metathesis catalysts
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Nitride- and alkylidyne complexes of molybdenum endowed with triarylsilanolate ligands are excellent (pre)catalysts for alkyne-metathesis reactions of all sorts, since they combine high activity with an outstanding tolerance toward polar and/or sensitive functional groups. Structural and reactivity data suggest that this promising application profile results from a favorable match between the characteristics of the high-valent molybdenum center and the electronic and steric features of the chosen Ar3SiO groups. This interplay ensures a well-balanced level of Lewis acidity at the central atom, which is critical for high activity. Moreover, the bulky silanolates, while disfavoring bimolecular decomposition of the operative alkylidyne unit, do not obstruct substrate binding. In addition, Ar3SiO groups have the advantage that they are more stable within the coordination sphere of a high-valent molybdenum center than tert-alkoxides, which commonly served as ancillary ligands in previous generations of alkyne metathesis catalysts. From a practical point of view it is important to note that complexes of the general type [(Ar3SiO)3Mo≡X] (X = N, CR; R = aryl, alkyl, Ar = aryl) can be rendered air-stable with the aid of 1,10-phenanthroline, 2,2'-bipyridine or derivatives thereof. Although the resulting adducts are themselves catalytically inert, treatment with Lewis acidic additives such as ZnCl2 or MnCl2 removes the stabilizing N-donor ligand and gently releases the catalytically active template into the solution. This procedure gives excellent results in alkyne metathesis starting from air-stable and hence user-friendly precursor complexes. The thermal and hydrolytic stability of representative molybdenum alkylidyne and -nitride complexes of this series was investigated and the structure of several decomposition products elucidated. Active yet tamed: Molybdenum benzylidyne complexes endowed with triarylsilanolates as ancillary ligands are superbly active and exquisitely selective alkyne metathesis catalysts, but can be rendered air-stable by reversible complexation with 1,10-phenanthroline or 2,2'-bipyridine (see, e.g., figure). A systematic molecular editing of their basic structural motif furnished a "library" of such catalysts and gave detailed insights into the parameters determining their favorable application profile. Copyright
- Heppekausen, Johannes,Stade, Robert,Kondoh, Azusa,Seidel, Guenter,Goddard, Richard,Fuerstner, Alois
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supporting information; scheme or table
p. 10281 - 10299
(2012/10/08)
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- Highly active multidentate alkyne metathesis catalysts: Ligand-activity relationship and their applications in efficient synthesis of porphyrin-based aryleneethynylene polymers
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A series of tris(arylmethyl)ammonium-coordinated molybdenum(VI) propylidyne catalysts was synthesized. Such N-quarternized multidentate catalysts showed high robustness, strong resistance to small alkyne polymerization and significantly enhanced catalytic activity compared to their corresponding tris(arylmethyl)amine-based analogues. The high activity of these new catalysts also enabled the efficient synthesis of ethynylene-bridged porphyrin-based arylene ethynylene polymers via alkyne metathesis, which represents a highly efficient, defect-free, viable approach for the synthesis of this class of intriguing polymers. Copyright
- Jyothish, Kuthanapillil,Wang, Qi,Zhang, Wei
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supporting information
p. 2073 - 2078,6
(2020/09/02)
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- Mild Pd/Cu-catalyzed sila-sonogashira coupling of (hetero)aryl bromides with (hetero)arylethynylsilanes under PTC conditions
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The palladium/copper cocatalyzed sila-Sonogashira reaction of (hetero)arylethynysilanes with (hetero)aryl bromides in toluene and water at 40 C under PTC conditions gave the required di(hetero)arylethynes in moderate to high yields. Activated, deactivated and ortho-substituted (hetero)aryl bromides are well tolerated. This protocol also allowed the preparation of symmetrical diarylethynes by double arylation of 1,2-bis(trimethylsilyl)ethyne. Georg Thieme Verlag Stuttgart · New York.
- Bellina, Fabio,Lessi, Marco
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experimental part
p. 773 - 777
(2012/07/01)
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- Calcium carbide as a cost-effective starting material for symmetrical diarylethynes via Pd-catalyzed coupling reaction
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A convenient and cost-effective synthetic method for symmetrical diarylethynes from inexpensive calcium carbide and aryl iodide has been developed. The reaction not only proceeds with high yield and selectivity but also tolerates a wide range of functional groups. Application of this reaction has enabled the synthesis of highly functionalized oligo (phenyleneethynylenes) to be accomplished.
- Chuentragool, Padon,Vongnam, Kunnigar,Rashatasakhon, Paitoon,Sukwattanasinitt, Mongkol,Wacharasindhu, Sumrit
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experimental part
p. 8177 - 8182
(2011/10/31)
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- HEPATITIS C VIRUS INHIBITORS
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The present disclosure is generally directed to antiviral compounds, and more specifically directed to compounds which can inhibit the function of the NS5A protein encoded by Hepatitis C virus (HCV), compositions comprising such compounds, and methods for inhibiting the function of the NS5A protein
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Page/Page column 271
(2011/07/30)
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- Pd-catalyzed [2+2+1] coupling of alkynes and arenes: Phenol diazonium salts as mechanistic trapdoors
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Alkynes and phenol diazonium salts undergo a Pd-catalyzed [2+2+1] cyclization reaction to spiro[4,5]decatetraene-7-ones. This structure was confirmed for one example by X-ray single-crystal structure analysis. The reaction is believed to proceed through oxidative addition of the phenol diazonium cation to Pd0, subsequent insertion of two alkynes, followed by irreversible spirocyclization. Copyright
- Schmidt, Bernd,Berger, Rene,Kelling, Alexandra,Schilde, Uwe
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supporting information; experimental part
p. 7032 - 7040
(2011/07/30)
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- Introducing a podand motif to alkyne metathesis catalyst design: A highly active multidentate molybdenum(VI) catalyst that resists alkyne polymerization
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Podand prevents polymers: The molybdenum(VI) propylidyne catalyst 1 with a podand triphenolamine ligand shows high activity in the metathesis of a variety of alkyne substrates, including heterocycles that contain donor moieties. With one substrate-binding site blocked by the multidentate ligand, the undesired polymerization of small alkynes that occurs with non-podand-ligand complex 2 is completely inhibited. Copyright
- Jyothish, Kuthanapillil,Zhang, Wei
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supporting information; experimental part
p. 3435 - 3438
(2011/05/04)
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- Direct CC Triple Bond Formation from the C=C Double Bond and Direct Hydroxylation into the o-Position of a Nitro Group on the Benzene Nucleus with Potassium t-Butoxide in N,N-DImethylformamide in the Air
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A novel and facile method for direct CC acetylenic bond formation from the C=C double bond by treatment with potassium t-butoxide (t-BuOK) in N,N-dimethylformamide in the air has been found in a 9,10-bis(4-substituted styryl)anthracene series, in 4-substituted 4'-nitrostilbene series, and in 1-(p-nitrophenyl)-4-(p-substituted phenyl)-1,3-butadiene series; its scope and limitations have been examined.The ESR spectrum of the reaction against 4-diethylamino-4'-nitrostilbene was measured to identify an anion radical specied expected for explanation of the mechanism of the dehydrogention reaction.Further, cyclic voltammetric measurements of a series of stilbenes and diphenylacetylenes were carried out in connection with the abovw mechanism.In many cases, interestingly, the use of a large excess of t-BuOH brought about succeeding hydroxylation into the ortho-position of a nitro group on the benzene nucleus.The simple hydroxylation is useful for the synthesis of substituted 5-(arylethynyl)-2-nitrophenols, which are expected to function as non-linear optical materials with the corresponding non-hydroxy compounds.The ultraviolet-visible and fluorescence spectral properties were measured and discussed also with those of the related compounds.
- Akiyama, Shuzo,Tajima, Kunihiko,Nakatsuji, Shin'ichi,Nakashima, Kenichiro,Abiru, Kazuko,Watanabe, Miwa
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p. 2043 - 2052
(2007/10/03)
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- Oxidation of Aromatic Compounds. IV. Oxidation of Symmetrical Diarylacetylenes in the CF3COOH-CH2Cl2-PbO2 System. A New One-Pot Synthesis of 1,2,3,4-Tetraaryl-2-butene-1,4-diones
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Oxidation of symmetrical diarylacetylenes in the CF3COOH-CH2Cl2-PbO2 system (0-20 deg C, 1-3 h) yields 1,2,3,4-tetraaryl-2-butene-1,4-diones.According to (1)H NMR and GC-MS data the compounds synthesized have Z configuration.
- Rudenko, A. P.,Vasil'ev, A. V.
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p. 1360 - 1379
(2007/10/03)
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- Electron-transfer versus Nucleophilic Substitution in the Reactions of α-Halogenated 4-Nitrotoluenes with Base
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A comparative study of the reactions of 4-nitrobenzyl and 4-nitrobenzylidene halides (ArCHXY; Ar = 4-NO2C6H4-; X = H or Halogen; Y = Halogen) with alkali shows that the reaction is sensitive to the nature of the side chain halogen substituent(s) as well as the reaction conditions.In alcoholic alkali, only 4-nitrobenzyl chloride (ArCH2Cl) reacts smoothly via the electron transfer (ET)-radical pathway to give mainly dimeric products while the corresponding bromide (ArCH2Br) and iodide (ArCH2I) give exclusively SN products.The ET pathway is enhanced for these substrates by the application of phase-transfer catalysis.In the case of the 4-nitrobenzylidene dihalides (ArCHXY; X = Y = Cl; X = Cl, Y = Br; X = Y = Br; X = F, Y = Br) it is also shown that although progressive bromine substitution suppresses the ET pathway, application of phase-transfer catalysis minimises competing solvolytic reactions and enhances the radical reaction.
- Kam, Toh-Seok,Lim, Tuck-Meng
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p. 147 - 150
(2007/10/02)
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- The Correlation of Regiochemistry with Structure in the SRN1 Reaction of aci-Nitronates with p-Nitrobenzylic Substrates
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The rate and regiochemistry of the SRN1 reactions of aci-nitronates with p-nitrobenzylic substrates are profoundly affected by branching at the positions adjacent to the reaction sites (Cβ).Definitive rules which predict whether C-alkylation will occur in the association step involving p-nitrobenzylic radicals and aci-nitronate ions are formulated. β-Branching causes O-alkylation or reductive processes to increase.In some cases no recognizable product formation results.Benzylic alcohols, p-nitrophenyl alkyl ketones and/or their oximes, and p-nitrophenol are among the products which result from subsequent reactions of the O-alkylation products, aci-nitronic esters of benzylic alcohols.
- Norris, Robert K.,Randles, David
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p. 1621 - 1633
(2007/10/02)
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- SYNTHESIS OF SYMMETRICAL TOLANES FROM BENZILIDENE BROMIDES
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The main relationships govering the formation of symmetrical tolanes during the condensation of benzylidene bromides under the influence of strong bases in dipolar aprotic solvents were investigated.The reaction takes place through the formation of α,α'-dibromostilbenes, which are debrominated to tolanes under these conditions.
- Vernigor, E. M.,Shalaev, V. K.,Luk'yanets, E. A.
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p. 317 - 321
(2007/10/02)
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