107740-92-1Relevant articles and documents
Borenium ionic liquids as catalysts for Diels-Alder reaction: Tuneable Lewis superacids for catalytic applications
Matuszek,Coffie,Chrobok,Swad?ba-Kwa?ny
, p. 1045 - 1049 (2017)
Ionic liquids based on the tricoordinate borenium cation were used for the first time as Lewis acid catalysts for a model Diels-Alder reaction. The conversion of the dienophile was successfully correlated with the Gutmann acceptor number values of the ionic liquids. Borenium ionic liquids exceeded the performance of catalysts reported in the literature.
Diels-Alder Reactions in Aqueous Solutions. Enforced Hydrophobic Interactions between Diene and Dienophile
Blokzijl, Wilfried,Blandamer, Michael J.,Engberts, Jan B. F. N.
, p. 4241 - 4246 (1991)
Second-order rate constants and isobaric activation parameters for the intermolecular Diels-Alder reactions of cyclopentadiene with alkyl vinyl ketones (2a,b) and 5-substituted-1,4-naphthoquinones (3a-c) as well as for the intramolecular Diels-Alder reaction of N-furfuryl-N-methylmaleamic acid (4) were determined in water, monohydric alcohols, and highly aqueous solutions containing monohydric alcohols and other organic cosolvents. The intermolecular as well as the intramolecular Diels-Alder reaction are characterized by large rate accelerations upon going from an organic solvent to water as the reaction medium. A model for solvation effects on rate constants for Diels-Alder reactions in aqueous solutions is developed. The typical, huge rate enhancements for Diels-Alder reactions in water and in highly aqueous binary mixtures are significantly sensitive to substituent effects and are discussed in terms of enforced pairwise hydrophobic interactions between diene and dienophile.
Biodegradable pyridinium ionic liquids: Design, synthesis and evaluation
Harjani, Jitendra R.,Singer, Robert D.,Garcia, M. Teresa,Scammells, Peter J.
, p. 83 - 90 (2009)
A range of ionic liquids (ILs) with a pyridinium cation were synthesised and their biodegradability was evaluated using the CO2 Headspace test (ISO 14593). ILs bearing an ester side chain moiety were prepared from either pyridine or nicotinic acid and showed high levels of biodegradation under aerobic conditions and can be classified as 'readily biodegradable'. In contrast, pyridinium ILs with alkyl side chains showed significantly lower levels of biodegradability in the same test. The utility of the biodegradable IL 6c as a reaction solvent for the Diels-Alder reaction was also investigated.
Electrostatically enhanced phosphoric acids: A tool in Br?nsted acid catalysis
Ma, Jie,Kass, Steven R.
, p. 5812 - 5815 (2016)
A novel type of phosphoric acid catalyst with enhanced reactivity is reported. These compounds possess one or two positively charged centers which electrostatically activate them. This is illustrated in several bond-forming transformations including Friedel-Crafts and Diels-Alder reactions as well as a ring-opening polymerization. Rate accelerations corresponding to orders of magnitude are observed.
An in-depth look at the effect of Lewis acid catalysts on Diels-Alder cycloadditions in ionic liquids
Silvero, Guadalupe,Arévalo, María José,Bravo, José Luis,ávalos, Martín,Jiménez, José Luis,López, Ignacio
, p. 7105 - 7111 (2005)
The present work explores in detail the Diels-Alder reaction between cyclopentadiene and a series of dienophiles, performed in an innovative medium such as an ionic liquid. The potential activation of different Lewis acid catalysts and their load effect when used in combination with this solvent have been explored, in order to settle the improvement on rates and selectivities.
A simple route to selective Diels-Alder reactions using modified zeolite Y
Najafi, H. Mahmoudi,Ghandi,Farzaneh
, p. 358 - 359 (2000)
Synthetically useful Diels-Alder reactions of different dienophiles with cyclopentadiene in the presence of chirally modified zeolite Y as simple and accessible medium led to high rate and diastereoselectivity and low to moderate enantioselectivity.
Lewis acids based on sulfur containing boron heterocycles and trialkylthioboranes
Howarth, Joshua,Helmchen, Gunter,Kiefer, Mattias
, p. 4095 - 4096 (1993)
The use of trialkyl- and aryl- thioboranes, along with 2-substituted 1,3,2-dithioborolans as Lewis acids has not previously been explored. The article describes the use of four such compounds in the Lewis acid catalysed Diels-Alder reactions of cyclopentadiene with crotonaldehyde, methacrolein, methylvinyl ketone and methylmethacrylate.
SELECTIVE DIELS-ALDER REACTIONS IN AQUEOUS SOLUTIONS AND SUSPENSIONS
Breslow, Ronald,Maitra, Uday,Rideout, Darryl
, p. 1901 - 1904 (1983)
Diels-Alder reactions show high endo/exo selectivities in aqueous suspensions.
Metal Bis((perfluoroalkyl)sulfonyl)amides as Novel Lewis Acid Catalysts in Diels-Alder Reaction
Kobayashi, Hiroshi,Nie, Jin,Sonoda, Takaaki
, p. 307 - 308 (1995)
Some stable and lipophilic metal bis((perfluoroalkyl)-sulfonyl)amides are prepared and employed as remarkable Lewis acid catalysts in the Diels-Alder reaction of cyclopentadiene with methyl vinyl ketone.
Silica-Promoted Diels-Alder Reactions in Carbon Dioxide from Gaseous to Supercritical Conditions
Weinstein, Randy D.,Renslo, Adam R.,Danheiser, Rick L.,Tester, Jefferson W.
, p. 2878 - 2887 (1999)
Amorphous fumed silica (SiO2) was shown to increase yields and selectivities of several Diels-Alder reactions in gaseous and supercritical CO2. Pressure effects on the Diels-Alder reaction were explored using methyl vinyl ketone and penta-1,3-diene at 80°C. The selectivity of the reaction was not affected by pressure/ density. As pressure was increased, the yield decreased. At the reaction temperature, adsorption isotherms at various pressures were obtained for the reactants and the Diels-Alder adduct. As expected when pressure is increased, the ratio of the amount of reactants adsorbed to the amount of reactants in the fluid phase decreases, thus causing the yield to decrease. The Langmuir adsorption model fit the adsorption data. The Langmuir equilibrium partitioning constants all decreased with increasing pressure. The effect of temperature on adsorption was experimentally determined and traditional heats of adsorption were calculated. However, since supercritical CO2 is a highly compressible fluid, it is logical to examine the effect of temperature at constant density. In this case, entropies of adsorption were obtained. The thermodynamic properties that influence the real enthalpy and entropy of adsorption were derived. Methods of doping the silica and improving yields and selectivities were also explored.
Clay catalysis of the non-aqueous diels-alder reaction and the importance of humidity control
Collet, Christine,Laszlo, Pierre
, p. 2905 - 2908 (1991)
Unmodified kaolin clays are a simple and viable alternative to ferric ion-exchanged montmorillonites as catalysts for the normal electron demand Diels-Alder reaction. Water is the enemy: at 1 - 2 % levels, the stereoselectivity drops by a factor two or three.
Hexameric capsule of a resorcinarene bearing fluorous feet as a self-assembled nanoreactor: A Diels-Alder reaction in a fluorous biphasic system
Shimizu, Shoichi,Usui, Asuka,Sugai, Masae,Suematsu, Yuki,Shirakawa, Seiji,Ichikawa, Hayato
, p. 4734 - 4737 (2013)
A Diels-Alder reaction in a fluorous biphasic system was accelerated by a hexameric capsule of resorcinarene bearing fluorous feet. The reaction takes place predominantly within the capsule, which can be recovered as a fluorous solution and recycled after simple decantation. Copyright
N-hexylpyridinium bis(trifluoromethylsulfonyl)imide and Lewis acids - Catalytic systems for Diels-Alder reaction
Bittner, Bozena,Janus, Ewa,Milchert, Eugeniusz
, p. 192 - 198 (2011)
A comparative study of the Diels-Alder reactions between cyclopentadiene (1) and dienophiles (2 a - c) in N-hexylpyridinium bis(trifluoromethylsulfonyl) imide in a temperature range of 20-45°C is reported. The reaction rate constants and activation energies were calculated. Moreover, the catalytic systems based on N-hexylpyridinium bis(trifluoromethylsulfonyl)imide and Lewis acids were tested as a reaction media to perform the Diels-Alder reaction. Yb, Y, Mg, Zn triflates and chlorides (0.005 to 0.1 mmol) were used as catalysts. The recycling of catalytic system consisted of YCI3 and ionic liquid was performed. Versita Sp. z o.o.
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Nakazaki,M. et al.
, p. 1229 - 1233 (1976)
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Bismuth(III) Chloride or Triflate-Catalyzed Dienophilic Activity of α-Ethylenic Aldehydes and Ketones
Garrigues, Bernard,Gonzaga, Ferdinand,Robert, Helene,Dubac, Jacques
, p. 4880 - 4882 (1997)
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Bis-selenonium Cations as Bidentate Chalcogen Bond Donors in Catalysis
He, Xinxin,Wang, Xinyan,Tse, Ying-Lung Steve,Ke, Zhihai,Yeung, Ying-Yeung
, p. 12632 - 12642 (2021/10/21)
Lewis acids are frequently employed in catalysis but they often suffer from high moisture sensitivity. In many reactions, catalysts are deactivated because of the problem that strong Lewis acids also bond to the products. In this research, hydrolytically stable bidentate Lewis acid catalysts derived from selenonium dicationic centers have been developed. The bis-selenonium catalysts are employed in the activation of imine and carbonyl groups in various transformations with good yields and selectivity. Lewis acidity of the bis-selenonium salts was found to be stronger than that of the monoselenonium systems, attributed to the synergistic effect of the two cationic selenonium centers. In addition, the bis-selenonium catalysts are not inhibited by strong bases or moisture.
Stereoselectivity in a series of 7-alkylbicyclo[3.2.0]hept-2-enes: Experimental and computational perspectives
Leber, Phyllis,Kidder, Katherine,Viray, Don,Dietrich-Peterson, Eric,Fang, Yuan,Davis, Alexander
, (2018/08/03)
Rate constants for overall decomposition (kd) for a series of exo-7-alkylbicyclo[3.2.0]hept-2-enes are relatively invariant. For the alkyl substituents ethyl, propyl, butyl, isopropyl, and t-butyl, the ratio of the rate constant for [1,3] sigmatropic rearrangement to the rate constant for fragmentation, k13/kf, is significantly lower than k13/kf?=?150 observed for exo-7-methylbicyclo[3.2.0]hept-2-ene. Regardless of the size and mass of the alkyl group, the stereoselectivity of the [1,3] carbon migration appears to be quite stable at 80% to 89% suprafacial inversion (si), an observation consistent with conservation of angular momentum but not conservation of orbital symmetry. This global result comports with the phenomenon of “dynamic matching” espoused by Carpenter and collaborators for [1,3] sigmatropic rearrangements in general.
