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Robert H Grubbs - One of the best experts on this subject based on the ideXlab platform.
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high trans kinetic selectivity in ruthenium based olefin Cross Metathesis through stereoretention
Organic Letters, 2016Co-Authors: Adam M Johns, Robert H Grubbs, Tonia S Ahmed, Bradford W Jackson, Richard L. PedersonAbstract: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.
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z selective Cross Metathesis with ruthenium catalysts synthetic applications and mechanistic implications
Angewandte Chemie, 2015Co-Authors: Myles B. Herbert, Robert H GrubbsAbstract:Olefin Cross Metathesis is a particularly powerful transformation that has been exploited extensively for the formation of complex products. Until recently, however, constructing Z-olefins using this methodology was not possible. With the discovery and development of three families of ruthenium-based Z-selective catalysts, the formation of Z-olefins using Metathesis is now not only possible but becoming increasingly prevalent in the literature. In particular, ruthenium complexes containing cyclometalated NHC architectures developed in our group have been shown to catalyze various Cross Metathesis reactions with high activity and, in most cases, near perfect selectivity for the Z-isomer. The types of Cross Metathesis reactions investigated thus far are presented here and explored in depth.
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Z‐Selective Cross Metathesis with Ruthenium Catalysts: Synthetic Applications and Mechanistic Implications
Angewandte Chemie (International ed. in English), 2015Co-Authors: Myles B. Herbert, Robert H GrubbsAbstract:Olefin Cross Metathesis is a particularly powerful transformation that has been exploited extensively for the formation of complex products. Until recently, however, constructing Z-olefins using this methodology was not possible. With the discovery and development of three families of ruthenium-based Z-selective catalysts, the formation of Z-olefins using Metathesis is now not only possible but becoming increasingly prevalent in the literature. In particular, ruthenium complexes containing cyclometalated NHC architectures developed in our group have been shown to catalyze various Cross Metathesis reactions with high activity and, in most cases, near perfect selectivity for the Z-isomer. The types of Cross Metathesis reactions investigated thus far are presented here and explored in depth.
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Ruthenium-catalysed Z-selective Cross Metathesis of allylic-substituted olefins
Chemical science, 2014Co-Authors: Brendan L. Quigley, Robert H GrubbsAbstract:The Z-selective Cross Metathesis of allylic-substituted olefins is explored with recently developed ruthenium-based Metathesis catalysts. The reaction proceeds with excellent stereoselectivity for the Z-isomer (typically >95%) and yields of up to 88% for a variety of allylic substituents. This includes the first synthesis of Z-α,β-unsaturated acetals by Cross Metathesis and their elaboration to Z-α,β-unsaturated aldehydes. In addition, the reaction is tolerant of a variety of Cross partners, varying in functionality and steric profile.
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olefin Cross Metathesis
Reference Module in Chemistry Molecular Sciences and Chemical Engineering#R##N#Comprehensive Organometallic Chemistry III#R##N#From Fundamentals to Ap, 2007Co-Authors: Robert H Grubbs, Anna G Wenzel, Arnab K. ChatterjeeAbstract:Olefin Cross-Metathesis has become an indispensable tool for efficient carbon–carbon bond formation. Fundamental studies on functional group tolerance and an understanding of the steric and electronic factors crucial to product selectivity have led to the development of an empirical model for reaction design. Due to the copious amount of recent literature pertaining to this reaction, this review focuses on reports pertaining to important aspects in either the concept or the application of alkene Cross-Metathesis. Strategies for effecting highly selective Cross-Metathesis reactions will be presented and discussed.
Christian Bruneau - One of the best experts on this subject based on the ideXlab platform.
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Cross Metathesis of bio-sourced fatty nitriles with acrylonitrile.
Chemical Monthly / Monatshefte für Chemie, 2015Co-Authors: Johan Bidange, Jean Luc Dubois, Christian Bruneau, Cédric Fischmeister, Jean-Luc CouturierAbstract:We report the Cross Metathesis of two olefinic partners contg. different types of nitrile functionality. Thus, Cross Metathesis of fatty nitriles with acrylonitrile have been achieved with olefin Metathesis ruthenium catalysts. 10-Undecenenitrile provides 2-dodecenedinitrile with a high turnover no. of 13,280 in the green solvent, di-Et carbonate. Cross Metathesis with the internal carbon-carbon double bond of oleonitrile gave the expected products, and the cleavage of the internal double bond proved to be more difficult probably owing to faster catalyst decomposition.
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Cross Metathesis of bio-sourced fatty nitriles with acrylonitrile.
Chemical Monthly Monatshefte für Chemie, 2015Co-Authors: Johan Bidange, Jean Luc Dubois, Christian Bruneau, Cédric Fischmeister, Jean-Luc CouturierAbstract:We report the Cross Metathesis of two olefinic partners contg. different types of nitrile functionality. Thus, Cross Metathesis of fatty nitriles with acrylonitrile have been achieved with olefin Metathesis ruthenium catalysts. 10-Undecenenitrile provides 2-dodecenedinitrile with a high turnover no. of 13,280 in the green solvent, di-Et carbonate. Cross Metathesis with the internal carbon-carbon double bond of oleonitrile gave the expected products, and the cleavage of the internal double bond proved to be more difficult probably owing to faster catalyst decomposition.
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Cross Metathesis of bio-sourced fatty nitriles with acrylonitrile
Monatshefte für Chemie - Chemical Monthly, 2015Co-Authors: Johan Bidange, Jean Luc Dubois, Christian Bruneau, Cédric Fischmeister, Jean-Luc CouturierAbstract:We report the Cross Metathesis of two olefinic partners containing different types of nitrile functionality. Thus, Cross Metathesis of fatty nitriles with acrylonitrile have been achieved with olefin Metathesis ruthenium catalysts. 10-Undecenenitrile provides 2-dodecenedinitrile with a high turnover number of 13,280 in the green solvent, diethyl carbonate. Cross Metathesis with the internal carbon–carbon double bond of oleonitrile gave the expected products, and the cleavage of the internal double bond proved to be more difficult probably owing to faster catalyst decomposition. Graphical abstract
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Cross Metathesis of unsaturated epoxides for the synthesis of polyfunctional building blocks
Beilstein Journal of Organic Chemistry, 2015Co-Authors: Meriem K. Abderrezak, Christian Bruneau, Kristýna Šichová, Nancy Dominguez-boblett, Antoine Dupé, Zahia Kabouche, Cédric FischmeisterAbstract:The Cross Metathesis of 1,2-epoxy-5-hexene (1) with methyl acrylate and acrylonitrile was investigated as an entry to the synthesis of polyfunctional compounds. The resulting Cross Metathesis products were hydrogenated in a tandem fashion employing the residual ruthenium from the Metathesis step as the hydrogenation catalyst. Interestingly, the epoxide ring remained unreactive toward this hydrogenation method. The saturated compound resulting from the Cross Metathesis of 1 with methyl acrylate was transformed by means of nucleophilic ring-opening of the epoxide to furnish a diol, an alkoxy alcohol and an amino alcohol in high yields
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Cross-Metathesis of fatty acid methyl esters with acrolein: An entry to a variety of bifunctional compounds
European Journal of Lipid Science and Technology, 2014Co-Authors: Hélène Bonin, Jean Luc Dubois, Cédric Fischmeister, Adel Keraani, Markus Brandhorst, Christian BruneauAbstract:The Cross-Metathesis of renewable fatty acid methyl esters with acrolein was investigated. The bifunctional formyl-esters obtained are interesting compounds for further transformations into bifunctional polymer precursors. Several experimental parameters and ruthenium catalysts have been evaluated. Best results were obtained with thermally pre-treated fatty acid methyl esters (FAMEs). The reactions performed with high efficiency with low catalyst loadings allowing TONs as high at 1000. An acetal protected acrolein was also used, enabling improvement of the reaction performances. A tandem Cross-Metathesis/hydrogenation reaction without isolation of the formyl intermediate delivered the expected alcohol ester in good yield. Practical applications: The Cross-Metathesis of FAMEs with acrolein provides access to a broad range of bifunctional compounds of interest for the manufacture of polymers, considering the multiple post-transformations of the formyl group available The ruthenium-catalyzed Cross-Metathesis of fatty acid methyl esters with acrolein is presented. The bifunctional formyl-esters are valuable precursors for subsequent transformations such as the tandem Cross-Metathesis/hydrogenation reaction delivering a hydroxyl-ester in one step.
Sangho Park - One of the best experts on this subject based on the ideXlab platform.
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Tandem sequence of Cross Metathesis--ring-closing Metathesis reaction of alkynyl silyloxy-tethered enynes.
Journal of the American Chemical Society, 2005Co-Authors: Sangho ParkAbstract:A tandem Cross Metathesis (CM)--ring-closing Metathesis (RCM) sequence to form cyclic siloxanes is reported. This new enyne Metathesis platform expands the scope and utility of the regio- and stereoselective Cross Metathesis reaction between silylated alkynes and terminal alkenes. The initial Cross Metathesis was directed to occur on the alkyne by employing sterically hindered mono-, di-, and trisubstituted alkenes tethered to the alkyne via silyl ether. The regio- and stereoselectivity feature of the initial CM step in this tandem CM-RCM process is identical to that of the CM reactions of silylated alkynes and alkenes. This tandem sequence provides both synthetically useful silylated 1,3-diene building blocks and insights into the reaction mechanism of the enyne Metathesis reaction.
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Regio- and stereoselective enyne Cross Metathesis of silylated internal alkynes.
Journal of the American Chemical Society, 2004Co-Authors: Mansuk Kim, Sangho Park, Sarah V. Maifeld, Daesung LeeAbstract:Cross Metathesis between silylalkynes and various functionalized alkenes catalyzed by Grubbs carbene complex produced, in most cases, single regio- and stereoisomers of the resultant 1,3-dienes. Polar heteroatom substituents at the propargylic site are important for high reactivity and selectivity. An important mechanistic insight regarding the initiation event and the key propagating alkylidene in this reaction was obtained by employing a tandem Cross Metathesis ring-closing Metathesis between a terminal alkene and a silylated alkyne possessing an alkene tether.
Steven T Diver - One of the best experts on this subject based on the ideXlab platform.
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Alkenol-alkyne Cross Metathesis.
Organic letters, 2008Co-Authors: Daniel A. Clark, Joseph R. Clark, Steven T DiverAbstract:Allyl alcohols and their homologues were used in the enyne Cross Metathesis to prepare hydroxy-functionalized dienes. An isomerization was found to occur under prolonged heating, and a method for conversion to (E)-diene product is also reported.
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Tandem dienyne Cross-Metathesis/ring-closing Metathesis
Tetrahedron Letters, 2001Co-Authors: Jason A. Smulik, Steven T DiverAbstract:Abstract Tandem enyne Cross-Metathesis/ring-closing Metathesis between terminal alkynes and 1,5-hexadiene has been demonstrated using the 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene-substituted ruthenium benzylidene complex. Synthesis of 2-substituted 1,3-cyclohexadienes using this one step tandem reaction is reported. In addition, Metathesis products were subjected to [4+2] cycloaddition with N -methylmaleimide yielding the corresponding cycloadducts in one synthetic step.
Cédric Fischmeister - One of the best experts on this subject based on the ideXlab platform.
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Cross Metathesis of bio-sourced fatty nitriles with acrylonitrile.
Chemical Monthly / Monatshefte für Chemie, 2015Co-Authors: Johan Bidange, Jean Luc Dubois, Christian Bruneau, Cédric Fischmeister, Jean-Luc CouturierAbstract:We report the Cross Metathesis of two olefinic partners contg. different types of nitrile functionality. Thus, Cross Metathesis of fatty nitriles with acrylonitrile have been achieved with olefin Metathesis ruthenium catalysts. 10-Undecenenitrile provides 2-dodecenedinitrile with a high turnover no. of 13,280 in the green solvent, di-Et carbonate. Cross Metathesis with the internal carbon-carbon double bond of oleonitrile gave the expected products, and the cleavage of the internal double bond proved to be more difficult probably owing to faster catalyst decomposition.
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Cross Metathesis of bio-sourced fatty nitriles with acrylonitrile.
Chemical Monthly Monatshefte für Chemie, 2015Co-Authors: Johan Bidange, Jean Luc Dubois, Christian Bruneau, Cédric Fischmeister, Jean-Luc CouturierAbstract:We report the Cross Metathesis of two olefinic partners contg. different types of nitrile functionality. Thus, Cross Metathesis of fatty nitriles with acrylonitrile have been achieved with olefin Metathesis ruthenium catalysts. 10-Undecenenitrile provides 2-dodecenedinitrile with a high turnover no. of 13,280 in the green solvent, di-Et carbonate. Cross Metathesis with the internal carbon-carbon double bond of oleonitrile gave the expected products, and the cleavage of the internal double bond proved to be more difficult probably owing to faster catalyst decomposition.
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Cross Metathesis of bio-sourced fatty nitriles with acrylonitrile
Monatshefte für Chemie - Chemical Monthly, 2015Co-Authors: Johan Bidange, Jean Luc Dubois, Christian Bruneau, Cédric Fischmeister, Jean-Luc CouturierAbstract:We report the Cross Metathesis of two olefinic partners containing different types of nitrile functionality. Thus, Cross Metathesis of fatty nitriles with acrylonitrile have been achieved with olefin Metathesis ruthenium catalysts. 10-Undecenenitrile provides 2-dodecenedinitrile with a high turnover number of 13,280 in the green solvent, diethyl carbonate. Cross Metathesis with the internal carbon–carbon double bond of oleonitrile gave the expected products, and the cleavage of the internal double bond proved to be more difficult probably owing to faster catalyst decomposition. Graphical abstract
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Cross Metathesis of unsaturated epoxides for the synthesis of polyfunctional building blocks
Beilstein Journal of Organic Chemistry, 2015Co-Authors: Meriem K. Abderrezak, Christian Bruneau, Kristýna Šichová, Nancy Dominguez-boblett, Antoine Dupé, Zahia Kabouche, Cédric FischmeisterAbstract:The Cross Metathesis of 1,2-epoxy-5-hexene (1) with methyl acrylate and acrylonitrile was investigated as an entry to the synthesis of polyfunctional compounds. The resulting Cross Metathesis products were hydrogenated in a tandem fashion employing the residual ruthenium from the Metathesis step as the hydrogenation catalyst. Interestingly, the epoxide ring remained unreactive toward this hydrogenation method. The saturated compound resulting from the Cross Metathesis of 1 with methyl acrylate was transformed by means of nucleophilic ring-opening of the epoxide to furnish a diol, an alkoxy alcohol and an amino alcohol in high yields
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Cross-Metathesis of fatty acid methyl esters with acrolein: An entry to a variety of bifunctional compounds
European Journal of Lipid Science and Technology, 2014Co-Authors: Hélène Bonin, Jean Luc Dubois, Cédric Fischmeister, Adel Keraani, Markus Brandhorst, Christian BruneauAbstract:The Cross-Metathesis of renewable fatty acid methyl esters with acrolein was investigated. The bifunctional formyl-esters obtained are interesting compounds for further transformations into bifunctional polymer precursors. Several experimental parameters and ruthenium catalysts have been evaluated. Best results were obtained with thermally pre-treated fatty acid methyl esters (FAMEs). The reactions performed with high efficiency with low catalyst loadings allowing TONs as high at 1000. An acetal protected acrolein was also used, enabling improvement of the reaction performances. A tandem Cross-Metathesis/hydrogenation reaction without isolation of the formyl intermediate delivered the expected alcohol ester in good yield. Practical applications: The Cross-Metathesis of FAMEs with acrolein provides access to a broad range of bifunctional compounds of interest for the manufacture of polymers, considering the multiple post-transformations of the formyl group available The ruthenium-catalyzed Cross-Metathesis of fatty acid methyl esters with acrolein is presented. The bifunctional formyl-esters are valuable precursors for subsequent transformations such as the tandem Cross-Metathesis/hydrogenation reaction delivering a hydroxyl-ester in one step.