- Supported Ru olefin metathesis catalysts: Via a thiolate tether
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Thiolate-coordinated ruthenium alkylidene complexes can give high Z-selectivity and stereoretentivity in olefin metathesis. To investigate their applicability as heterogeneous catalysts, we have successfully developed a methodology to easily immobilize prototype ruthenium alkylidenes onto hybrid mesostructured silica via a thiolate tether. In contrast, the preparation of the corresponding molecular complexes appeared very challenging in solution. These prototype supported complexes contain small thiolates but still, they are slightly more Z-selective than their molecular analogues. These results open the door to more active and selective heterogeneous catalysts by supporting more advanced thiolate Ru-complexes.
- Renom-Carrasco, Marc,Mania, Philipp,Sayah, Reine,Veyre, Laurent,Occhipinti, Giovanni,Gajan, David,Lesage, Anne,Jensen, Vidar R.,Thieuleux, Chloé
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supporting information
p. 2886 - 2890
(2019/03/07)
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- USE OF RUTHENIUM COMPLEXES IN OLEFIN METATHESIS REACTION
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The invention relates to the use of ruthenium complexes, which are homogeneous catalysts and/or precatalysts of the olefin metathesis reaction, which lead to the production of alkenes containing an internal (non-terminal) double C=C bond.
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Page/Page column 19
(2018/05/27)
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- SYNTHESIS AND CHARACTERIZATION OF METATHESIS CATALYSTS
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This invention relates generally to olefin metathesis catalysts, to the preparation of such compounds, compositions comprising such compounds, methods of using such compounds, and the use of such compounds in the metathesis of olefins and in the synthesis of related olefin metathesis catalysts. The invention has utility in the fields of catalysis, organic synthesis, polymer chemistry, and in industrial applications such as oil and gas, fine chemicals, and pharmaceuticals.
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Paragraph 000156; 000157
(2018/03/25)
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- Synthesis and Catalytic Properties of Sulfur-Chelated Ruthenium Benzylidenes Bearing a Cyclic (Alkyl)(amino)carbene Ligand
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Sulfur-chelated ruthenium olefin metathesis precatalysts that possess cyclic (alkyl)(amino)carbenes (CAAC) can benefit from the synergetic effect of both ligands. Changing the steric bulk of the CAAC ligand by using different substitution patterns was shown to affect the geometry of the complexes produced and determined whether the complexes could be catalytically dormant. The cis-dichloro latent catalysts could be activated both by heat or light, even in the visible region, for representative acyclic diene metathesis and ring-opening metathesis polymerization reactions, olefin cross-metathesis, and ring-closing metathesis without isomerization byproducts. Thus, these complexes were shown to combine the uniqueness of CAAC-containing Ru olefin metathesis catalysts with the advantage of the thermal and photolatency imposed by sulfur chelation of the benzylidene.
- Rozenberg, Illya,Eivgi, Or,Frenklah, Alexander,Butilkov, Danielle,Kozuch, Sebastian,Goldberg, Israel,Lemcoff, N. Gabriel
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p. 8182 - 8191
(2018/09/06)
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- Stereoretentive Olefin Metathesis Made Easy: In Situ Generation of Highly Selective Ruthenium Catalysts from Commercial Starting Materials
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The in situ preparation of highly stereoretentive ruthenium-based metathesis catalysts is reported. This approach completely avoids the isolation of intermediates and air-sensitive catalysts, thus allowing for the rapid access and evaluation of numerous dithiolate Ru catalysts. A procedure was established to perform cross-metathesis reactions without the use of a glovebox, and on a small scale even Schlenk techniques are not required. Consequently, the chemistry displayed in this report is available to every practicing organic chemist and presents a powerful approach for the identification of new stereoretentive catalysts.
- Müller, Daniel S.,Curbet, Idriss,Raoul, Yann,Le N?tre, Jér?me,Baslé, Olivier,Mauduit, Marc
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supporting information
p. 6822 - 6826
(2018/10/31)
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- Synthesis and Evaluation of Sterically Demanding Ruthenium Dithiolate Catalysts for Stereoretentive Olefin Metathesis
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Dithiolate ligands have recently been used in ruthenium-catalyzed olefin metathesis and have provided access to a kinetically E selective pathway through stereoretentive olefin metathesis. The typical dithiolate used is relatively simple with low steric demands imparted on the catalyst. We have developed a synthetic route that allows access to sterically demanding dithiolate ligands. The catalysts generated provided a pathway to study the intricate structure-activity relationships in olefin metathesis. It was found that DFT calculations can predict the ligand arrangement around the ruthenium center with remarkable accuracy. These dithiolate catalysts proved resistant to ligand isomerization and were stable even under forcing conditions. Additionally, catalyst initiation and olefin metathesis studies delivered a better understanding to the interplay between dithiolate ligand structure and catalyst activity and selectivity.
- Montgomery, T. Patrick,Grandner, Jessica M.,Houk,Grubbs, Robert H.
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p. 3940 - 3953
(2017/10/31)
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- Fast-initiating, ruthenium-based catalysts for improved activity in highly E-selective cross metathesis
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Ruthenium-based olefin metathesis catalysts bearing dithiolate ligands have been recently employed to generate olefins with high E-selectivity (>99% E) but have been limited by low to moderate yields. In this report, 1H NMR studies reveal that a major contributing factor to this low activity is the extremely low initiation rates of these catalysts with trans olefins. Introducing a 2-isopropoxy-3-phenylbenzylidene ligand in place of the conventional 2-isopropoxybenzylidene ligand resulted in catalysts that initiate rapidly under reaction conditions. As a result, reactions were completed in significantly less time and delivered higher yields than those in previous reports while maintaining high stereoselectivity (>99% E).
- Ahmed, Tonia S.,Grubbs, Robert H.
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supporting information
p. 1532 - 1537
(2017/02/10)
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- OLEFIN METATHESIS CATALYSTS
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This invention relates generally to metathesis catalysts and the use of such catalysts in the metathesis of olefins and olefin compounds, more particularly, in the use of such catalysts in Z and E selective olefin metathesis reactions. The invention has utility in the fields of organometallics and organic synthesis.
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Page/Page column 76; 77
(2017/07/06)
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- Cross metathesis of methyl oleate (MO) with terminal, internal olefins by ruthenium catalysts: Factors affecting the efficient MO conversion and the selectivity
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Cross metathesis (CM) reactions of methyl oleate (MO) with cis-4-octene (OC), cis-stilbene (CS) using RuCl2(PCy3)(IMesH2)(CHPh) [IMesH2 = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene; Cy = cyclohexyl] afforded CM products with high MO conversion and high selectivity under high molar (OC/MO, CS/MO) ratios; CM with cis-1,4-diacetoxy-2-butene also afforded metathesis products with high MO conversion under certain conditions. The efficient CM with allyltrimethylsilane proceeded with high activity, whereas the CM with glycidyl ether, β-pinene, and vanillylidenacetone proceeded with low MO conversion.
- Awang, Nor Wahida,Tsutsumi, Ken,Hu?táková, Barbora,Yusoff, Siti Fairus M.,Nomura, Kotohiro,Yamin, Bohari M.
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p. 100925 - 100930
(2016/11/09)
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- High Trans Kinetic Selectivity in Ruthenium-Based Olefin Cross-Metathesis through Stereoretention
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The first kinetically controlled, highly trans-selective (>98%) olefin cross-metathesis reaction is demonstrated using Ru-based catalysts. Reactions with either trans or cis olefins afford products with highly trans or cis stereochemistry, respectively. This E-selective olefin cross-metathesis is shown to occur between two trans olefins and between a trans olefin and a terminal olefin. Additionally, new stereoretentive catalysts have been synthesized for improved reactivity. (Chemical Equation Presented).
- Johns, Adam M.,Ahmed, Tonia S.,Jackson, Bradford W.,Grubbs, Robert H.,Pederson, Richard L.
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supporting information
p. 772 - 775
(2016/03/01)
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- One-pot direct synthesis route to self-assembled highly ordered Zn-decorated mesoporous aluminium oxide toward efficient and sustainable metathesis heterogeneous catalyst design
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Hexagonally well-organized ZnCl2-OMA materials have been successfully synthesized by a one-pot approach using a sol-gel method at ambient temperature and pressure. These materials were prepared through simultaneous self-assembly process with F127 as directing agent combined with in situ impregnation of ZnCl2. The new approach was found to be compatible with various common aluminium precursors and carboxylic acids used as self-assembly interfacial protectors. The obtained ZnCl2-OMA materials were fully characterized using XRD, N2 adsorption-desorption, TEM, SEM, EDX, XPS and 1H and 27Al MAS-NMR techniques. These materials were compared with the zinc chloride-doped organized mesoporous alumina (ZnCl2-OMA) supports prepared through a conventional two steps process that includes OMA synthesis and then post-synthesis incorporation of ZnCl2. Thus, the one-pot synthesized materials were found to exhibit improved properties compared to the conventional ones, particularly larger BET surface area. The synthesized ZnCl2-OMA materials were then used as catalytic supports for methyltrioxorhenium (MTO), showing enhanced catalytic performance for methyl oleate self-metathesis, demonstrating better activity and selectivity towards desired metathesis products. These features are highly beneficial for large-scale materials synthesis through fast, simple, easy and low-cost introduction of functionalities on mesoporous materials surface without multi-step procedures.
- Abidli, Abdelnasser
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p. 92743 - 92756
(2015/11/16)
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- Synthesis, characterization and insights into stable and well organized hexagonal mesoporous zinc-doped alumina as promising metathesis catalysts carrier
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A series of highly ordered hexagonal mesoporous alumina and zinc-modified mesoporous alumina samples are synthesized via a sol-gel method through an evaporation-induced self-assembly process using Pluronic F127 as nonionic templating agent and several aluminum precursors. The process was mediated using several carboxylic acids along with hydrochloric acid in ethanol. Successful impregnation of ZnCl2 was achieved while maintaining the ordered structure. The surface and textural properties of the materials were investigated. N2-physisorption analysis revealed a BET surface area of 394 m2 g-1 and a pore volume around 0.55 cm3 g-1. Moreover, small-angle XRD diffraction patterns highlighted the well-organized hexagonal structure even upon the incorporation of zinc chloride. The organized-structure arrangement was further confirmed by transmission electron microscopy (TEM) analysis. The Zn/Al composition of the final materials was confirmed by EDX and XPS analysis, and the zinc amount incorporated was analyzed by ICP. Furthermore, the surface modification with zinc chloride impregnation was analyzed by XPS, 1H and 27Al MAS-NMR and FTIR spectroscopic techniques. In addition, the effects of synthesis conditions and the mechanism of the mesostructure formation were explored. The catalytic activity of several methyltrioxorhenium (MTO)-based catalysts supported on these hexagonal mesoporous alumina materials was tested for methyl oleate self-metathesis. The results showed improved kinetics using hexagonal alumina in comparison to those using wormhole-like alumina counterparts. This behavior could be attributed to better mass transfer features of hexagonal mesoporous alumina. The prepared materials with desirable pore size and structure are suitable candidates as catalyst supports for metathesis of bulky functionalized olefins and other catalytic transformations due to their enhanced Lewis acidity and more uniform pore networks favoring enhanced and selective mass transfer phenomena.
- Abidli, Abdelnasser,Hamoudi, Safia,Belkacemi, Khaled
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p. 9823 - 9838
(2015/06/08)
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- Metathesis of methyloleate over methyltrioxorhenium supported on ZnCl 2-promoted mesoporous alumina
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Methyltrioxorhenium impregnated on ZnCl2-modified mesoporous alumina at Al/Zn ratio of 8-12 was revealed as an effective catalyst for self-metathesis of methyloleate at mild reaction conditions. The use of other promoters either in form of metal chlorides or as other zinc halides did not promote the metathesis of methyloleate as zinc chloride. The enhancement of the activity was not only due to the chloride and/or zinc but could be attributed to the interaction of both elements as Zn-Cl or ZnCl2 bonds with the mesoporous alumina. The results of this research suggest that it is possible to design a heterogeneous catalyst for the efficient and selective self-metathesis of functionalized olefins such as methyloleate and edible oils, avoiding the utilization of expensive homogeneous catalysts or use of toxic promoters such as SnR4 with heterogeneous catalysts.
- Pillai, Subha Kumaraswamy,Hamoudi, Safia,Belkacemi, Khaled
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p. 155 - 163
(2013/05/22)
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- A dicationic ruthenium alkylidene complex for continuous biphasic metathesis using monolith-supported ionic liquids
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A dicationic ruthenium-alkylidene complex [Ru(dmf)3(IMesH 2)(=CH-2-(2-PrO)-C6H4)][(BF4) 2] (1; IMesH2=1,3-dimesitylimidazolin-2-ylidene) has been prepared and used in continuous metathesis reactions by exploiting supported ionic-liquid phase (SILP) technology. For these purposes, ring-opening metathesis polymerization (ROMP)-derived monoliths were prepared from norborn-2-ene, tris(norborn-5-ene-2-ylmethyloxy)methylsilane, and [RuCl 2(PCy3)2(CHPh)] (Cy=cyclohexyl) in the presence of 2-propanol and toluene and surface grafted with norborn-5-en-2-ylmethyl-N,N, N-trimethylammonium tetrafluoroborate ([NBE-CH2-NMe 3][BF4]). Subsequent immobilization of the ionic liquid (IL), 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([BDMIM][BF 4]), containing ionic catalyst 1 created the SILP catalyst. The use of a second liquid transport phase, which contained the substrate and was immiscible with the IL, allowed continuous metathesis reactions to be realized. High turnover numbers (TONs) of up to 3700 obtained in organic solvents for the ring-closing metathesis (RCM) of, for example, N,N-diallyltrifluoroacetamide, diethyl diallylmalonate, diethyl di(methallyl)malonate, tert-butyl-N,N- diallylcarbamate, N,N-diallylacetamide, diphenyldiallylsilane, and 1,7-octadiene, as well as in the self-metathesis of methyl oleate, could be further increased by using biphasic conditions with [BDMIM][BF 4]/heptane. Under continuous SILP conditions, TONs up to 900 were observed. Due to the ionic character of the initiator, catalyst leaching into the transport phase was very low (4]/1, the recycled support material again qualified for utilization in continuous metathesis reactions. Copyright
- Autenrieth, Benjamin,Frey, Wolfgang,Buchmeiser, Michael R.
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p. 14069 - 14078
(2013/01/15)
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- Libraries via Metathesis of Internal Olefins
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The cross-metathesis of internal olefins is applied for the combinatorial synthesis of small organic molecules; this reaction is conveniently carried out in neat olefin (oleic-acid derivatives) and requires only 0.001 equiv. of [Ru(CHPh)Cl2(PCy3)2] as catalyst (Cy = cyclohexyl).
- Braendli, Christof,Ward, Thomas R.
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p. 1616 - 1621
(2007/10/03)
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- Synthesis of a Palm-Based Star-Shaped Hydrocarbon via Oleate Metathesis
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10,11-Dioctyleicosane, a star-shaped hydrocarbon, has been successfully synthesized from 9-octadecene (a product from metathesis of methyl oleate or ethyl oleate) through dimerization followed by hydrogenation.The product was determined by 13C nuclear magnetic resonance spectroscopic and gas chromatography/mass spectrometric techniques.This hydrocarbon likely exhibits lubricating properties that can be used as high-performance functional fluids in automotive lubrication.We also report the presence of a novel product, a trimer that was formed during the synthesis. - Key words: Diethyl 9-octadecenedioate; 10,11-dioctyl eicosane; ethyl and methyl oleates; metathesis; 9-octadecene; palm oil; star-shaped hydrocarbon.
- Choo, Yuen-May,Ooi, Kay-Eng,Ooi, Ing-Hong,Tan, Daniel D. H.
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p. 333 - 336
(2007/10/03)
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- An Iridium-based Catalyst System for Metathesis/Isomerization of Acyclic Olefins, including Methyl Oleate
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Reaction between 2 (coe = cyclooctene) and AgO2CCF3 (4 equiv.) produces a highly active system for metathesis/isomerization of acyclic olefins, including methyl oleate.
- France, Marcia B.,Feldman, Jerald,Grubbs, Robert H.
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p. 1307 - 1308
(2007/10/02)
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- Metathesis of Functionalized Alkenes. Synthesis of Insect Pheromones
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The ability of substituted phenoxy complexes of tungsten to effect metathesis of both functionalized and non-functionalized terminal alkenes has been investigated.This methodology has been applied to the synthesis of the insect pheromones tetradec-9-en-1-yl acetate, dodec-7-en-1-yl acetate and tricos-9-ene.
- Crisp, Geoffrey T.,Collis, Maree P.
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p. 935 - 942
(2007/10/02)
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- REDUCTION OF THIIRANES TO ALKENES AND ALKANES
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Various reagents were tested in order to reduce thiiranes to alkanes or olefins.The results of this investigation is presented in this letter.
- Schauder, J.R.,Denis, J.N.,Krief, A.
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p. 1657 - 1660
(2007/10/02)
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- METATHESIS REACTIONS OF UNSATURATED ESTERS CATALYZED BY HOMOGENEOUS TUNGSTEN COMPLEXES. SYNTHESES OF CIVETONE AND MACROLIDES
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The metathesis reactions of methyl 10-undecenoate, methyl oleate and oleyl acetate have been carried out using WCl6 and WOCl4 as primary catalysts and SnMe4, PbMe4, Cp2TiMe2, and Cp2ZrMe2 as cocatalysts.The catalyst system WOCl4/Cp2TiMe2 was found to be very active for the metathesis of the unsaturated esters and is somewhat better than the system WCl6/SnMe4.Diethyl 9-octadecene-1,18-dioate, obtained by the metathesis of ethyl oleate, was subjected to the Dieckmann cyclization.The cyclized product was decarboxylated to give civetone as a mixture of the cis and trans isomers.Preliminary studies of macrolide synthesis by the intramolecular metathesis of oleyl oleate and 10-undecenyl 10-undecenoate to afford 9-octadecen-18-olide and 10-eicosen-20-olide, respectively, have been carried out.
- Tsuji, Jiro,Hashiguchi, Shohei
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- Cometathesis of Methyl Oleate and Ethylene; a Direct Route to Methyl Dec-9-enoate
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Methyl dec-9-enoate is obtained by cometathesis of ethylene and methyl oleate with two different catalyst systems, viz.WCl6-Me4Sn and Re2O7-Al2O3-Me4Sn; at 0.2 MPa ethylene pressure both catalyst systems show good activity at 343 K and the latter system also at room temperature.
- Bosma, Ruud H. A.,Aardweg, Fred van den,Mol, Johannes C.
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p. 1132 - 1133
(2007/10/02)
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