- Palladium-catalyzed regio- and stereoselective synthesis of N-protected 2,4-dialkylated azacyclobutanes from amino allenes
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Palladium-catalyzed reaction of N-arylsulfonyl-1-alkyl-3,4-dienylamines with an aryl iodide in the presence of potassium carbonate in DMF at around 70°C affords most predominantly the 2,4-cis-disubstituted azacyclobutanes bearing an aryl group on the doub
- Anzai, Miyuki,Toda, Ayako,Ohno, Hiroaki,Takemoto, Yoshiji,Fujii, Nobutaka,Ibuka, Toshiro
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Read Online
- Activated Hoveyda-Grubbs Olefin Metathesis Catalysts Derived from a Large Scale Produced Pharmaceutical Intermediate – Sildenafil Aldehyde
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Two EWG-activated Hoveyda-Grubbs-type ruthenium complexes (Sil-II and Sil-II’) were obtained, characterized, and screened in a set of olefin metathesis reactions. These catalysts were conveniently synthesized from a commercially available pharmaceutical building block – Sildenafil aldehyde – in two steps only. Stability and catalytic activity tests disclosed that the bulkier NHC-ligand bearing catalyst Sil-II’ is visibly more stable and productive than its smaller NHC-analogue Sil-II. Good application profile of catalyst Sil-II’ was confirmed in a set of diverse metathesis reactions including ring-closing metathesis (RCM) and cross-metathesis (CM) of complex polyfunctional substrates of medicinal chemistry interest, including a challenging macrocyclization of the Pacritinib precursor. Compatibility of the new catalyst with various green solvents was checked and metathesis of Sildenafil and Tadalafil-based substrates was successfully conducted in acetone. The mechanism of Sil-II’ initiation has been investigated through kinetic experiments unveiling that the decrease of the steric hindrance of the chelating alkoxy moiety (from iPrO to EtO) favors the interchange initiation pathway over the typical dissociation pathway for other popular 2nd generation Hoveyda-Grubbs catalysts. (Figure presented.).
- Monsigny, Louis,Pi?tkowski, Jakub,Trzybiński, Damian,Wo?niak, Krzysztof,Niena?towski, Tomasz,Kajetanowicz, Anna,Grela, Karol
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supporting information
p. 4590 - 4604
(2021/08/13)
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- Olefination via Cu-Mediated Dehydroacylation of Unstrained Ketones
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The dehydroacylation of ketones to olefins is realized under mild conditions, which exhibits a unique reaction pathway involving aromatization-driven C-C cleavage to remove the acyl moiety, followed by Cu-mediated oxidative elimination to form an alkene between the α and β carbons. The newly adopted N′-methylpicolinohydrazonamide (MPHA) reagent is key to enable efficient cleavage of ketone C-C bonds at room temperature. Diverse alkyl- and aryl-substituted olefins, dienes, and special alkenes are generated with broad functional group tolerance. Strategic applications of this method are also demonstrated.
- Dong, Guangbin,Xu, Yan,Zhou, Xukai
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supporting information
p. 20042 - 20048
(2021/12/03)
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- Merging Halogen-Atom Transfer (XAT) and Cobalt Catalysis to Override E2-Selectivity in the Elimination of Alkyl Halides: A Mild Route towardcontra-Thermodynamic Olefins
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We report here a mechanistically distinct tactic to carry E2-type eliminations on alkyl halides. This strategy exploits the interplay of α-aminoalkyl radical-mediated halogen-atom transfer (XAT) with desaturative cobalt catalysis. The methodology is high-yielding, tolerates many functionalities, and was used to access industrially relevant materials. In contrast to thermal E2 eliminations where unsymmetrical substrates give regioisomeric mixtures, this approach enables, by fine-tuning of the electronic and steric properties of the cobalt catalyst, to obtain high olefin positional selectivity. This unprecedented mechanistic feature has allowed access tocontra-thermodynamic olefins, elusive by E2 eliminations.
- Zhao, Huaibo,McMillan, Alastair J.,Constantin, Timothée,Mykura, Rory C.,Juliá, Fabio,Leonori, Daniele
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supporting information
p. 14806 - 14813
(2021/09/18)
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- Regiocontrolled Reductive Vinylation of Aliphatic 1,3-Dienes with Vinyl Triflates by Nickel Catalysis
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The regiocontrolled functionalization of 1,3-dienes has become a powerful tool for divergent synthesis, yet it remains a long-standing challenge for aliphatic substrates. Herein, we report a reductive approach for a branch-selective 1,2-hydrovinylation of aliphatic 1,3-dienes with R-X electrophiles, which represents a new selectivity pattern for diene functionalization. Simple butadiene, aromatic 1,3-dienes, and highly conjugated polyene were also tolerated. The combination of Ni(0) and the phosphine-nitrile ligand generally resulted in >20:1 regioselectivity with the retention of the geometry of the C3-C4 double bonds. This reaction proceeds with a broad substrate scope, and it allows for the conjugation of two biologically active units to form more complex polyene molecules, such as tetraene and pentaene as well as heptaene.
- Pang, Xiaobo,Zhao, Zhen-Zhen,Wei, Xiao-Xue,Qi, Liangliang,Xu, Guang-Li,Duan, Jicheng,Liu, Xue-Yuan,Shu, Xing-Zhong
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supporting information
p. 4536 - 4542
(2021/04/07)
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- Triphenylphosphine-Catalyzed Alkylative Iododecarboxylation with Lithium Iodide under Visible Light
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Under irradiation of 456 nm blue light-emitting diodes, PPh3 catalyzes the iododecarboxylation of aliphatic carboxylic acid derived N-(acyloxy)phthalimide with lithium iodide as an iodine source. The reaction delivers primary, secondary, and bridgehead te
- Fu, Ming-Chen,Shang, Rui,Wang, Jia-Xin
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- Nickel-Catalyzed Cyanation of Unactivated Alkyl Sulfonates with Zn(CN)2
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Cyanation of unactivated primary and secondary alkyl mesylates with Zn(CN)2 catalyzed by nickel has been developed. The reaction provides an efficient route for the synthesis of alkyl nitriles with wide substrate scope, good functional group tolerance, and compatibility with heterocyclic compounds. Mechanistic studies indicate that alkyl iodide generated in situ serves as the reactive intermediate and the gradual release of alkyl iodide is crucial for the success of the reaction.
- Xia, Aiyou,Lv, Peizhuo,Xie, Xin,Liu, Yuanhong
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p. 7842 - 7847
(2020/11/02)
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- Design of bis-NHC Ru-complexes featuring diarylmethylene N-substituents for olefin metathesis
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New ruthenium indenylidene complexes containing N-heterocyclic carbene (NHC) ligands were synthesized and evaluated in olefin metathesis. The presence of two symmetrical saturated NHCs featuring N-diarylmethylene fragments (R= H, OMe or F) led to robust ruthenium precatalysts with a good latency. A kinetic study was investigated showing that a thermal stimulus (>60 °C) is required to reach an efficient catalytic initiation. Interestingly, a slight electronic effect was observed depending on the presence of an electron-donating or –withdrawing group within the diarylmethylene moiety. These complexes showed good activity at 1 mol% of catalyst loading in selected ring-closing metathesis (RCM) and cross-metathesis (CM) transformations.
- Curbet, Idriss,Morvan, Jennifer,Colombel-Rouen, Sophie,Roisnel, Thierry,Crévisy, Christophe,Mauduit, Marc
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supporting information
p. 102 - 112
(2019/07/09)
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- Visible-Light-Controlled Ruthenium-Catalyzed Olefin Metathesis
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Olefin metathesis is now one of the most efficient ways to create new carbon-carbon bonds. While most efforts focused on the development of ever-more efficient catalysts, a particular attention has recently been devoted to developing latent metathesis cat
- Theunissen, Cédric,Ashley, Melissa A.,Rovis, Tomislav
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supporting information
(2019/05/08)
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- Visible-Light-Controlled Ruthenium-Catalyzed Olefin Metathesis
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Olefin metathesis is now one of the most efficient ways to create new carbon-carbon bonds. While most efforts focused on the development of ever-more efficient catalysts, a particular attention has recently been devoted to developing latent metathesis cat
- Theunissen, Cédric,Ashley, Melissa A.,Rovis, Tomislav
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supporting information
p. 6791 - 6796
(2019/05/10)
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- Electronic effects in mixed N-heterocyclic carbene/phosphite indenylidene ruthenium metathesis catalysts
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Five new complexes [RuCl2(SIMes)(Ind)(O-pXC5H4)] bearing different para-substituted triphenylphosphites (X = H, OCH3, CF3, Cl, SF5 and CN) were synthesised and used to study the effect of t
- Bidal, Yannick D.,Urbina-Blanco, César A.,Poater, Albert,Cordes, David B.,Slawin, Alexandra M.Z.,Cavallo, Luigi,Cazin, Catherine S.J.
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supporting information
p. 11326 - 11337
(2019/08/07)
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- Nitrogen-coordination-containing ruthenium carbene catalyst and preparation method and application thereof
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The present invention discloses a nitrogen-coordination-containing ruthenium carbene catalyst and a preparation method and application thereof. The nitrogen-coordination-containing ruthenium carbene catalyst is characterized by being shown in a formula (I
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Paragraph 0088; 0089; 0012
(2018/11/22)
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- Light-and Thermal-Activated Olefin Metathesis of Hindered Substrates
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Efficient light-and thermal-Activated metathesis reactions of tetra-substituted olefins were obtained by the S-chelated ruthenium precatalyst Tol-SCF3. Its reactivity in a series of benchmark olefin metathesis reactions was compared to previous
- Ivry, Elisa,Frenklah, Alexander,Ginzburg, Yakov,Levin, Efrat,Goldberg, Israel,Kozuch, Sebastian,Lemcoff, N. Gabriel,Tzur, Eyal
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p. 176 - 181
(2018/02/06)
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- Highly efficient and time economical purification of olefin metathesis products from metal residues using an isocyanide scavenger
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A sustainable protocol of olefin metathesis in non-degassed, undistilled ethyl acetate under air with commercially available self-scavenging ruthenium catalysts is described. Furthermore, a time economical, cost-effective and scalable method of removal of ruthenium residues is presented. Treatment of post-reaction mixtures with an isocyanide scavenger and then with acid followed by a simple filtration is shown to yield OM products with ruthenium contamination below 5 ppm even in highly challenging cases. Finally, a telescope RCM/Suzuki-Miyaura sequence with a rapid and efficient purification protocol for simultaneous removal of Ru and Pd residues from solution is described.
- Szczepaniak, Grzegorz,Ruszczyńska, Anna,Kosiński, Krzysztof,Bulska, Ewa,Grela, Karol
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supporting information
p. 1280 - 1289
(2018/03/28)
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- A process for the preparation and synthetic ChondriamideA and ChondriamideC method (by machine translation)
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The invention provides a process for the preparation of synthetic Chondriamide A and Chondriamide C and method, wherein the invention provides a process for the preparation, including: formula (I) compounds of structure, palladium catalyst, phosphorus ligand, alkali and organic solvent at room temperature the illumination reaction, formula (II) structure obtained olefin; wherein through the selection of a particular phosphorus ligand; make the method of the invention can be under the photocatalysis, room temperature to realize high-efficient catalytic conversion, and the mild reaction conditions, simple operation, in line with the development of green environment-friendly chemical requirements, and the range of choice of substrate and functional group compatibility has more universal, and has outstanding chemical selectivity; and the method can be successfully applied to complex molecular introducing carbon-carbon double bond to the programme, to optimize a part of the drug molecular synthesis strategy, improve the synthesis efficiency, reduce the cost, with industrial synthetic value and prospects. (by machine translation)
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Paragraph 0093-0097; 0115-0118
(2018/09/13)
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- GROUP 8 TRANSITION METAL CATALYSTS AND METHOD FOR MAKING SAME AND PROCESS FOR USE OF SAME IN OLEFIN DISPROPORTIONATION REACTIONS
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These catalyst compounds are represented by the formula (I and VI): wherein M is a Group 8 metal; X is an anionic ligand; L is a neutral two-electron donor ligand; A is a monotopic or ditopic chelating ligand. The present invention also relates to an easy applicable catalyst synthesis and the application in different olefin metathesis processes, e.g. Reaction Injection Molding (RIM), rotational molding, vacuum infusion, vacuum forming, process for conversion of fatty acids and fatty acid esters or mixtures thereof, in -olefins, dicarboxylic acids or dicarboxylic esters, etc.
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Page/Page column 54
(2017/12/09)
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- An Analogue of Grubbs Third-Generation Catalyst with Fluorophilic Pyridine Ligands: Fluorous/Organic Phase-Transfer Activation of Ring-Closing Alkene Metathesis
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The title catalyst (H2IMes)[3,5-NC5H3(CH2CH2Rf8)2]2(Cl)2Ru(=CHPh) [H2IMes=1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene, Rf8=(CF2)7CF3] was prepared from the fluorous pyridine 3,5-NC5H3(CH2CH2Rf8)2 (2.1 equiv.) and the pyridine complex (H2IMes)(NC5H5)2(Cl)2Ru(=CHPh). 3,5-NC5H3(CH2CH2Rf8)2 was synthesized by a Heck reaction of 3,5-dibromopyridine and the fluorous alkene H2C=CHRf8 [2.4 equiv.; Pd(OAc)2 (cat.), n-Bu4N+ Br-/NaOAc (2.0 equiv.)], followed by hydrogenation. The catalyst shows dramatic rate accelerations in the ring-closing metatheses of α,ω-dienes under fluorous/organic liquid/liquid biphasic conditions [e.g., perfluoro(methyldecalin)/CD2Cl2] relative to rates under monophasic organic conditions (e.g., CD2Cl2). These catalysts require initial dissociation of the pyridine ligands to generate the active species, which can either combine with an alkene (productive) or recombine with a pyridine (unproductive). In the case of (H2IMes)[3,5-NC5H2(CH2CH2Rf8)2]2(Cl)2Ru(=CHPh), fluorophilic 3,5-NC5H3(CH2CH2Rf8)2 transfers to the fluorous phase, in accord with its CF3C6F11/toluene partition coefficient [93.9:6.1 vs. 39.8:60.2 for (H2IMes)[3,5-NC5H3(CH2CH2Rf8)2]2(Cl)2Ru(=CHPh)], which decreases the fraction of unproductive events.
- Balogh, Janos,Hlil, Antisar R.,Su, Haw-Lih,Xi, Zhenxing,Bazzi, Hassan S.,Gladysz, John A.
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p. 125 - 128
(2016/01/25)
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- Highly efficient nitrogen chelated ruthenium carbene metathesis catalysts
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A series of nitrogen chelated ruthenium carbene metathesis catalysts containing an N-heterocyclic carbene (NHC) and a carbonyl group have been developed and their catalytic activities for olefin metathesis reactions were investigated. The X-ray structure of the [(H2IMes)(Cl)2Ru]C(H)CH2[p-F(C6H3)NC(CF3)(C(O)OCH2CH3)] complex shows that the carbonyl oxygen of the ester and the imine nitrogen are both coordinated to the Ru metal to give an octahedral structure. The catalytic activity of these ruthenium carbene complexes for olefin metathesis reactions was tested. Some of the complexes bearing electron withdrawing groups had high initiation rates. These complexes exhibited excellent performance for both ring-closing metathesis and cross metathesis.
- Duan, Yulian,Wang, Tao,Xie, Qingxiao,Yu, Xiaobo,Guo, Weijie,Wang, Jianhui,Liu, Guiyan
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p. 19441 - 19448
(2016/12/16)
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- A medium fluorous Grubbs-Hoveyda 2nd generation catalyst for phase transfer catalysis of ring closing metathesis reactions
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A fluorous Grubbs-Hoveyda metathesis catalyst supported on Teflon powder, that readily moves between the solid phase (Teflon) and the liquid phase (DMF) was prepared. By modulating the hydrophobicity of the reaction medium at the end of the reaction, the supported catalyst could be recovered by simple filtration even though the catalyst existed in a homogeneous state during the reaction. In RCM reactions, the catalyst could be reused up to three times with only a slight loss in reactivity with each subsequent cycle.
- Kobayashi, Yuki,Inukai, Sae,Kondo, Natsuki,Watanabe, Tomoko,Sugiyama, Yuya,Hamamoto, Hiromi,Shioiri, Takayuki,Matsugi, Masato
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supporting information
p. 1363 - 1366
(2015/03/04)
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- Synthesis and catalytic activity of a Grubbs-Hoveyda pre-catalyst having a trimeric resting state
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A Grubbs-Hoveyda pre-catalyst having a trimeric resting state based on 2,4,6-trichloro-1,3,5-triazine was synthesized and the complex was characterized by NMR, HRMS and elemental analysis. The activity of this complex for ring-closing metathesis (RCM) was
- Liu, Guiyan,Wu, Bin,Wang, Jianhui
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p. 441 - 445
(2015/04/22)
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- Synthesis and catalytic study of ruthenium carbene catalyst containing a Zn-porphyrin ligand
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A ruthenium carbene complex containing a Zn-porphyrin ligand has been developed. The complex was characterized by 1H NMR, IR, HRMS and elemental analysis. The catalytic activity of the ruthenium carbene complex for olefin metathesis reactions w
- Xu, Ying,Zhang, Huizhu,Wang, Xinyuan,Liu, Guiyan
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p. 1393 - 1397
(2016/02/18)
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- Conducting Olefin Metathesis Reactions in Air: Breaking the Paradigm
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The first study of low catalyst loading olefin metathesis reactions in air is reported. TON values of up to 7000 were obtained using nondegassed solvents with commercially available precatalysts Caz-1, Hov-II, and Ind-II. The simple experimental condition
- Guidone, Stefano,Songis, Olivier,Nahra, Fady,Cazin, Catherine S. J.
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p. 2697 - 2701
(2015/06/17)
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- The effect of silica-coating on catalyst recyclability in ionic magnetic nanoparticle-supported Grubbs-Hoveyda catalysts for ring-closing metathesis
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The Grubbs-Hoveyda type ruthenium-carbene complexes have been covalently immobilized on both silica coated and uncoated magnetic nanoparticles utilizing an imidazolium salt linker. These MNP-supported catalysts showed comparable catalytic activity to the
- Chen, Shu-Wei,Zhang, Zhi-Cheng,Zhai, Ning-Ning,Zhong, Chong-Min,Lee, Sang-Gi
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p. 648 - 653
(2015/02/02)
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- Exceptionally Stable and Efficient Solid Supported Hoveyda-Type Catalyst
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The ammonium tagged Hoveyda-type catalyst bearing sterically enlarged N-heterocyclic carbene ligand was synthesized and supported on SBA-15. The obtained heterogeneous olefin metathesis catalyst forms unprecedentedly stable Ru-methylidenes and provides products of ring-closing and cross metathesis with turnover numbers (TONs) up to 35 000 and turnover frequencies (TOFs) up to 1590 min-1. The catalyst proved to be truly recyclable and effective in a continuous flow mode.
- Skowerski, Krzysztof,Pastva, Jakub,Czarnocki, Stefan J.,Janoscova, Jana
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supporting information
p. 872 - 877
(2015/07/27)
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- Nitro-Grela-type complexes containing iodides -robust and selective catalysts for olefin metathesis under challenging conditions
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Iodide-containing nitro-Grela-type catalysts have been synthesized and applied to ring closing metathesis (RCM) and cross metathesis (CM) reactions. These new catalysts have exhibited improved efficiency in the transformation of sterically, nondemanding a
- Tracz, Andrzej,Matczak, Mateusz,Urbaniak, Katarzyna,Skowerski, Krzysztof
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supporting information
p. 1823 - 1832
(2016/04/19)
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- Modular, Concise, and Efficient Synthesis of Highly Functionalized 5-Fluoropyridazines by a [2 + 1]/[3 + 2]-Cycloaddition Sequence
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An easy access to 5-fluoropyridazines by a [2 + 1]/[3 + 2]-cycloaddition sequence between terminal alkynes, a difluorocarbene, and a diazo compound is reported. This approach does not necessitate the isolation of any intermediates, and a wide range of novel 5-fluoropyridazines was synthesized from readily available starting materials. Additionally, these compounds were used as a platform to access novel and highly diversified pyridazines.
- Tran, Ga?l,Gomez Pardo, Domingo,Tsuchiya, Tomoki,Hillebrand, Stefan,Vors, Jean-Pierre,Cossy, Janine
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supporting information
p. 3414 - 3417
(2015/07/28)
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- Synthesis, structure and catalytic study of oxygen chelated ruthenium (II) carbene complex
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New oxygen chelated ruthenium carbene complex containing carbonyl oxygen and ether oxygen has been developed. The X-ray structure of the complex showed that the carbonyl oxygen of the amide and the terminal oxygen of the benzylidene ether are both coordinated to the metal to give an octahedral structure. The catalytic activities of this new complex for olefin metathesis reactions were investigated and it exhibited excellent performances for the ring-closing metathesis (RCM) of diethyl diallymalonate at 30 °C and even at 0 °C. The initiation rate of the catalyst was higher than that for the Hoveyda catalyst ((H2IMes)(Cl)2Ru = C(H)(C6H 4-2-OiPr)) and it was also active for cross metathesis (CM).
- Liu, Guiyan,Shao, Mingbo,Zhang, Huizhu,Wang, Jianhui
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- RUTHENIUM POLYMERISATION CATALYSTS
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Cis and trans ruthenium complexes that can be used as catalysts for ring opening metathesis polymerisation (ROMP) are described. The complexes are generally square pyramidal in nature, having two anionic ligands X. Corresponding cationic complexes where one or both of the anionic ligands X are replaced by a non-co-ordinating anionic ligand are also described. Polymers such as polydicyclopentadiene (PDCPD) can be prepared using the catalysts.
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Paragraph 0096; 0097
(2014/08/19)
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- Efficient ruthenium metathesis catalysts containing carborane ligands
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A first generation Hoveyda-Grubbs ruthenium complex with a closo-1,2-C 2B10H11 tag has been prepared. This new catalyst was tested in ring-closing metathesis (RCM) reactions and proved to be quite efficient. In addition, t
- Liu, Guiyan,Zhang, Huizhu,Zhao, Xia,Wang, Jianhui
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- A six-coordinated cationic ruthenium carbyne complex with liable pyridine ligands: Synthesis, structure, catalytic investigation, and DFT study on initiation mechanism
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A novel six-coordinated high-valence cationic ruthenium carbyne complex bearing two liable pyridine ligands was prepared in high yield by the reaction of the ruthenium-based complex (IMesH2)(Cl)2(C 5H5N)2RuCHPh [IMesH2=1,3-dimesityl- 4,5-dihydroimida-zol-2-ylidene] with excess iodine as an oxidant in CH 2Cl2 at 25 °C under N2. The new ruthenium carbyne-based complex shows moderate to good catalytic activity for ring-closing metathesis reactions. Importantly, no double bond isomerization by-product was produced at elevated reaction temperatures (100 °C-137 °C) in the reaction catalyzed by the synthesized ruthenium carbyne complex. A mechanism involving the in situ conversion of the ruthenium carbyne through the addition of an iodide to the carbyne carbon was also proposed, and DFT calculations were performed to explain the initiating mechanism.
- Liu, Guiyan,Zheng, Lu,Shao, Mingbo,Zhang, Huizhu,Qiao, Weixia,Wang, Xiaojia,Liu, Bowen,Zhao, Haitao,Wang, Jianhui
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supporting information
p. 4718 - 4725
(2014/06/24)
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- Supported ruthenium-carbene catalyst on ionic magnetic nanoparticles for olefin metathesis
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The Grubbs-Hoveyda ruthenium-carbene complex has been covalently immobilized on ionic magnetic nanoparticles utilizing an imidazolium salt linker. The supported catalyst exhibited excellent catalytic activity for ring-closing metathesis (RCM) and cross-me
- Chen, Shu-Wei,Zhang, Zhi-Cheng,Ma, Miaofeng,Zhong, Chong-Min,Lee, Sang-Gi
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supporting information
p. 4969 - 4971
(2014/12/11)
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- Synthesis and reactivity of oxygen chelated ruthenium carbene metathesis catalysts
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The rate of initiation of Hoveyda catalysts is affected by the electronic and steric effects that act upon the Rua?O coordination. In order to boost the activity of Hoveyda catalysts, a series of new oxygen chelated ruthenium carbene metathesis catalysts containing an N-heterocyclic carbene (NHC) and a carbonyl group has been developed, and their catalytic activities for olefin metathesis reactions were investigated. The aliphatic end groups of complexes (H2IMes)(Cl)2RuC(H)[(C6H 3X)OCH(Me)(C(O)OEt)(X = H, OMe, Me, NO2)] were functionalized by the attachment of a straight-chain ester. The X-ray structures of complex (H2IMes)(Cl)2RuC(H)[(C6H 4)OCH(Me)(C(O)NMe2)] showed that the carbonyl oxygen of the amide and the terminal oxygen of the benzylidene ether are both coordinated to the metal to give an octahedral structure. However, the carbonyl oxygen of complexes (H2IMes)(Cl)2RuC(H)[(C6H 3X)OCH(CH2C(O)OCH2)(X = H, OMe)] does not coordinate to the metal due to the steric effect of the lactone. All these complexes were used as catalysts for olefin metathesis reactions and all exhibited excellent performances for the ring-closing metathesis (RCM) of diethyl diallymalonate at 30 C. The initiation rate of these catalysts was higher than that for the Hoveyda catalyst ((H2IMes)(Cl) 2RuC(H)(C6H4-2-OiPr)) and these complexes are also active for cross metathesis (CM).
- Zhang, Yiran,Shao, Mingbo,Zhang, Huizhu,Li, Yuqing,Liu, Dongyu,Cheng, Yu,Liu, Guiyan,Wang, Jianhui
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- CATALYST COMPLEXES WITH CARBENE LIGAND AND METHOD FOR MAKING SAME AND USE IN METATHESIS REACTION
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This invention relates to catalyst compounds and the synthesis and applications useful in olefin metathesis reactions. The catalyst compounds of the invention are represented by the formula (I): wherein M is a Group 8 metal; X1 and X2/sup
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Page/Page column 43
(2014/07/23)
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- SULFUR CHELATED RUTHENIUM COMPOUNDS USEFUL AS OLEFIN METATHESIS CATALYSTS
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Sulfur chelated ruthenium compounds represented by the following formula: wherein M indicates the ruthenium metal bound to a benzylidene carbon; R represents C1-C7 alkyl group or optionally substituted aryl; X1 and X2 each independently represent halogen; Y1 and Y2 each independently denote unsubstituted or alkyl-substituted phenyl; and Z independently represents hydrogen, electron withdrawing or electron donating substituent, with m being an integer from 1 to 4, and processes and compositions related thereto.
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Paragraph 0107
(2014/06/23)
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- Grubbs-type catalysts immobilized on SBA-15: A novel heterogeneous catalyst for olefin metathesis
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A series of novel heterogeneous olefin metathesis catalysts have been developed by immobilizing Ru species on SBA-15 mesoporous silica with tunable ordered pores and different textural properties. Various techniques such as X-ray diffraction, N2 adsorption-desorption, high resolution transmission electron microscopy have been used to characterize the physicochemical properties of the catalysts. The catalytic activity of thus prepared Ru-based catalysts has been studied in ring closing metathesis (RCM) and other metathesis reactions. Among these immobilized catalysts, the SBA-15 support with the largest pore size gives rise to the highest catalytic activity because the large pores are benefit for the diffusion of reactants and products. The immobilized Ru catalysts prove to be reusable in RCM reactions. Their catalytic activity is closely related to the confinement effect and high hydrophobicity of SBA-15 mesopores.
- Zhang, Huan,Li, Ying,Shao, Songxue,Wu, Haihong,Wu, Peng
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- Ionic CNT-supported Ru-carbene complex for recyclable ring-closing metathesis
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The ionic multi-walled carbon nanotubes (IM-f-MWCNTs), which were covalently functionalized with imidazolium salt, have been utilized as support materials for the immobilization of Hoveyda-type Ru-carbene complex. The catalytic activity and recyclability
- Lee, Sujin,Shin, Ju Yeon,Lee, Sang-Gi
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supporting information
p. 684 - 687
(2013/02/23)
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- Ring-closing metathesis reactions: Interpretation of conversion-time data
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Conversion-time data were recorded for various ring-closing metathesis (RCM) reactions that lead to five- or six-membered cyclic olefins by using different precatalysts of the Hoveyda type. Slowly activated precatalysts were found to produce more RCM product than rapidly activated complexes, but this comes at the price of slower product formation. A kinetic model for the analysis of the conversion-time data was derived, which is based on the conversion of the precatalyst (Pcat) into the active species (Acat), with the rate constant kact, followed by two parallel reactions: 1) the catalytic reaction, which utilizes Acat to convert reactants into products, with the rate k cat, and 2) the conversion of Acat into the inactive species (Dcat), with the rate kdec. The calculations employ two experimental parameters: the concentration of the substrate (c(S)) at a given time and the rate of substrate conversion (-dc(S)/dt). This provides a direct measure of the concentration of Acat and enables the calculation of the pseudo-first-order rate constants kact, kcat, and kdec and of k S (for the RCM conversion of the respective substrate by Acat). Most of the RCM reactions studied with different precatalysts are characterized by fast kcat rates and by the kdec value being greater than the kact value, which leads to quasistationarity for Acat. The active species formed during the activation step was shown to be the same, regardless of the nature of different Pcats. The decomposition of Acat occurs along two parallel pathways, a unimolecular (or pseudo-first-order) reaction and a bimolecular reaction involving two ruthenium complexes. Electron-deficient precatalysts display higher rates of catalyst deactivation than their electron-rich relatives. Slowly initiating Pcats act as a reservoir, by generating small stationary concentrations of Acat. Based on this, it can be understood why the use of different precatalysts results in different substrate conversions in olefin metathesis reactions. Copyright
- Thiel, Vasco,Wannowius, Klaus-Juergen,Wolff, Christiane,Thiele, Christina M.,Plenio, Herbert
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p. 16403 - 16414
(2013/12/04)
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- Synthesis and reactivity of ruthenium phosphite indenylidene complexes
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The synthesis of the four olefin metathesis precatalysts Caz-1a-d, featuring the NHC ligand N,N′-bis(2,4,6-trimethylphenyl)imidazolin-2- ylidene (SIMes) and four different phosphites (P(OiPr)3, P(OPh)3, P(OEt)3,
- Bantreil, Xavier,Urbina-Blanco, Cesar A.,Bidal, Yannick D.,Randall, Rebecca A. M.,Slawin, Alexandra M. Z.,Cazin, Catherine S. J.,Poater, Albert,Falivene, Laura,Cavallo, Luigi
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p. 7415 - 7426,12
(2020/10/15)
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- An unusual cationic Ru(ii) indenylidene complex and its Ru(iii) derivative - Efficient catalysts for high temperature olefin metathesis reactions
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The use of a mixed phosphite/N-heterocyclic carbene bearing ruthenium precursor permits the synthesis and characterisation of unprecedented four-coordinate Ru(ii) and Ru(iii) cationic complexes adopting an unusual sawhorse structure. The cationic Ru(ii) c
- Songis, Olivier,Slawin, Alexandra M. Z.,Cazin, Catherine S. J.
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supporting information; experimental part
p. 1266 - 1268
(2012/02/15)
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- A unique ruthenium carbyne complex: A highly thermo-endurable catalyst for olefin metathesis
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A cationic ruthenium carbyne complex was prepared and was found to initiate olefin metathesis reactions with good activities, which throws a new light on the design of a new type of ruthenium catalyst for RCM reactions. More importantly, no double bond isomerized by-product was observed even at elevated temperatures in reactions catalyzed by the new carbyne complex. A mechanism involving the in situ conversion of the ruthenium carbyne to a ruthenium carbene complex via addition of an iodide to the carbyne carbon was also proposed.
- Wang, Jianhui,Shao, Mingbo,Zheng, Lu,Qiao, Weixia,Wang, Jingjing
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supporting information
p. 2743 - 2750,8
(2012/12/12)
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- Synthesis, structure and catalytic study of chloro-bridged two-core ruthenium carbene complexes
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The reaction of a ruthenium carbide complex RuCl2(C:) (PCy 3)2 with [H(Et2O)x] +[BF4]- at a molar ratio of 1:2 produced a two-core ruthenium carbene complex {[RuCl(CHPCy3)(PCy 3)]2(μ-Cl)3}+·[BF 4]- (8) in the form of a yellow-green crystalline solid. After a ligand exchange reaction of 8 with LiBr, a bromide ruthenium carbene complex {[RuBr(CHPCy3)(PCy3)]2(μ-Cl) 3}+·[BF4]- (9) was obtained as a crystalline solid. Catalytic studies showed that both 8 and 9 are selective catalysts for ring closing metathesis of unsubstituted terminal dienes. More importantly, no isomerized byproduct was observed when 8, or 9 was used as the catalyst at an elevated temperature (137 °C), indicating that both 8 and 9 are chemo-selective catalysts for ring closing metathesis reactions.
- Qiao, Weixia,Shao, Mingbo,Wang, Jianhui
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experimental part
p. 197 - 202
(2012/08/27)
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- Comprehensive study on olefin metathesis in PEG as an alternative solvent under microwave irradiation
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Polyethylene glycols (PEGs) are non-toxic, biodegradable and sustainable organic solvents, which find a large application in the chemical and pharmaceutical industry. In this study, we present the ring-closing metathesis reaction (RCM) in PEG under microw
- Bantreil, Xavier,Sidi-Ykhlef, Mohammed,Aringhieri, Laura,Colacino, Evelina,Martinez, Jean,Lamaty, Frederic
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p. 113 - 118
(2012/11/13)
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- Catalytic and structural studies of hoveyda-grubbs type pre-catalysts bearing modified ether ligands
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Catalytic and crystallographic studies of Hoveyda-Grubbs type pre-catalysts M51TM and M52TM were performed. These two new instruments in the olefin metathesis catalyst toolbox were shown to be active at ambient temperature and at low loading, leading to c
- Guidone, Stefano,Blondiaux, Enguerr,Samojlowicz, Cezary,Gulajski, Lukasz,Dziorek, Mariusz Ke,Malinska, Maura,Pazio, Aleksandra,Wozniak, Krzysztof,Grela, Karol,Doppiu, Angelino,Cazin, Catherine S. J.
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supporting information
p. 2734 - 2742
(2013/01/15)
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- Synthesis of pyrimidine-modified NHC ruthenium-alkylidene catalysts and their application in RCM, CM, em and ROMP reactions
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A new type of N-heterocyclic carbene bearing ruthenium olefin metathesis catalyst was prepared through the incorporation of a chelated pyrimidinyl methylene subunit, in which electron-rich substituents were attached to stabilize the ruthenium complexes. These catalysts were successfully used in various types of olefin metathesis reactions, including ring-closing metathesis (RCM), cross-metathesis (CM), enyne metathesis (EM), and ring-opening metathesis polymerization (ROMP) reactions. The results therein showed that the presence of an electron-deficient pyrimidine structure greatly enhanced the new NHC ruthenium complexes' catalytic activities. New N-heterocyclic carbene bearing ruthenium olefin metathesis catalysts were synthesized and applied in various types of olefin metathesis reactions, including ring-closing metathesis, cross-metathesis, enyne metathesis, and ring-opening metathesis polymerization reactions. Copyright
- Wu, Guang-Long,Cao, Sheng-Li,Chen, Jian,Chen, Zili
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p. 6777 - 6784
(2013/01/15)
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- TPGS-750-M: A second-generation amphiphile for metal-catalyzed cross-couplings in water at room temperature
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An environmentally benign surfactant (TPGS-750-M), a diester composed of racemic α-tocopherol, MPEG-750, and succinic acid, has been designed and readily prepared as an effective nanomicelle-forming species for general use in metal-catalyzed cross-coupling reactions in water. Several "name" reactions, including Heck, Suzuki-Miyaura, Sonogashira, and Negishi-like couplings, have been studied using this technology, as have aminations, C-H activations, and olefin metathesis reactions. Physical data in the form of DLS and cryo-TEM measurements suggest that particle size and shape are key elements in achieving high levels of conversion and, hence, good isolated yields of products. This new amphiphile will soon be commercially available.
- Lipshutz, Bruce H.,Ghorai, Subir,Abela, Alexander R.,Moser, Ralph,Nishikata, Takashi,Duplais, Christophe,Krasovskiy, Arkady,Gaston, Ricky D.,Gadwood, Robert C.
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experimental part
p. 4379 - 4391
(2011/07/06)
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- Phosphites as ligands in ruthenium-benzylidene catalysts for olefin metathesis
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The use of phosphites in second generation, ruthenium-based olefin metathesis pre-catalysts leads to an improvement in catalyst stability and activity at low catalyst loadings.
- Schmid, Thibault E.,Bantreil, Xavier,Citadelle, Cecilia A.,Slawin, Alexandra M. Z.,Cazin, Catherine S. J.
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supporting information; experimental part
p. 7060 - 7062
(2011/08/22)
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- Studies of a soluble polyethylene glycol immobilized ruthenium catalyst in aqueous media
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We have developed an air-stable soluble polyethylene glycol bound ruthenium catalyst which performs efficient ring-closing metathesis in organic solvents as well as in aqueous media.
- Zaman, Shazia,Chen, Hongyuan,Abell, Andrew D.
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experimental part
p. 878 - 880
(2011/03/20)
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- Ligand isomerization in sulfur-chelated ruthenium benzylidenes
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cis-Dichloro-trans-dichloro isomerization was studied in sulfur-chelated ruthenium benzylidenes. The effect of solvents and additives on the isomerization process was analyzed. Notably, π-acid ligand molecules, dichloromethane, and polar solvents were found to significantly accelerate the isomerization rate. As expected, the cis-trans isomer equilibria had a strong effect on the olefin metathesis reactivity; the bulkier cis-dichloro catalysts, which show a larger amount of trans isomer in the equilibrium, were more reactive than their less bulky counterparts. This tendency was generally reversed in the isolated trans isomer series, where both steric factors and faster isomerization play a role in dictating the olefin metathesis reactivity. A better understanding of the trans-cis isomerization and the mechanism that governs reactivity in strongly chelated cis-dichloro ruthenium benzylidenes was obtained.
- Aharoni, Anna,Vidavsky, Yuval,Diesendruck, Charles E.,Ben-Asuly, Amos,Goldberg, Israel,Lemcoff, N. Gabriel
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experimental part
p. 1607 - 1615
(2011/04/26)
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- Surfactant-Enabled Transition Metal-Catalyzed Chemistry
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In one embodiment, the present application discloses mixtures comprising (a) water in an amount of at least 1% wt/wt of the mixture; (b) a transition metal catalyst; and (c) one or more solubilizing agents; and methods for using such mixtures for performing transition metal mediated bond formation reactions.
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- Thermomorphic polyethylene-supported olefin metathesis catalysts
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The preparation of polyethylene-oligomer (PEolig)-supported N-heterocyclic carbene ligands (NHCs) and their Ru complexes is described. These complexes are structurally analogous to their low molecular weight counterparts and can serve as thermo
- Hobbs, Christopher,Yang, Yun-Chin,Ling, Johnny,Nicola, Sally,Su, Haw-Lih,Bazzi, Hassan S.,Bergbreiter, David E.
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supporting information; experimental part
p. 3904 - 3907
(2011/10/09)
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- METHOD FOR IN-SITU FORMATION OF METATHESIS CATALYSTS
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Synthetic methods for the in-situ formation of olefin metathesis catalysts are disclosed, as well as the use of such catalysts in metathesis reactions of olefins and olefin compounds. In one aspect, a method is provided for synthesizing an organometallic
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Page/Page column 28
(2011/10/13)
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