51789-91-4

Upstream product

• 1629-58-9 4-penten-3-one 
• 542-92-7 cyclopenta-1,3-diene 
• 10467-10-4 ethylmagnesium iodide 
• 95-11-4 bicyclo<2.2.1>heptene-5 carbonitrile-2 
• 95-11-4 bicyclo[2.2.1]hept-5-ene-2-carbonitrile 
• 925-90-6 ethylmagnesium bromide 
• 22515-82-8 1-pentene-3-one ethylene acetal 
• 824-60-2 endo-2-acetyl-5-norbornene 
• 74-88-4 methyl iodide 
• 949015-29-6 2-ethyl-2--1,3-dioxolane 

Downstream Products

• 111099-13-9 anti 4,5 methyl-4 phenyl-5 trimethylsiloxy-5 pentene-1 one-3 
• 111099-13-9 syn 4,5 methyl-4 phenyl-5 trimethylsiloxy-5 pentene-1 one-3 
• 111099-08-2 endo (methyl-2 phenyl-3 trimethylsiloxy-3 propanone-1 yl)-5 bicyclo<2.2.1> heptene-2 
• 1629-58-9 4-penten-3-one 
• 918-85-4 3-hydroxy-3-methyl-1-pentene 
• 111099-13-9 methyl-4 phenyl-5 trimethylsiloxy-5 pentene-1 one-3 
• 111099-03-7 (2R,3S)-1-Bicyclo[2.2.1]hept-5-en-2-yl-3-hydroxy-2-methyl-3-phenyl-propan-1-one 
• 111099-03-7 exo (syn 2,3 hydroxy-3 methyl-2 phenyl-3 propanone-1 yl-1)-5 bicyclo<2.2.1>heptene-2 
• 111099-08-2 exo (syn 2,3 methyl-2 phenyl-3 trimethylsiloxy-3 propanone-1 yl-1)-5 bicyclo<2.2.1.>heptene-2 
• 111099-03-7 endo (hydroxy-3 methyl-2 phenyl-3 propanone-1 yl-1)-5 bicyclo<2.2.1>heptene-2 

Relevant academic research and scientific papers

Chiral protic imidazolium salts with a (-)-menthol fragment in the cation: Synthesis, properties and use in the Diels-Alder reaction

New chiral protic imidazolium salts containing a (1R,2S,5R)-(-)-menthol substituent in the cation and four different anions (chloride, hexafluorophosphate, trifluoromethanesulfonate and bis(trifluoromethylsulfonyl)imide) were efficiently prepared and exte

Bis-selenonium Cations as Bidentate Chalcogen Bond Donors in Catalysis

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.

Silylium ion-catalyzed challenging Diels-Alder reactions: The danger of hidden proton catalysis with strong Lewis acids

The pronounced Lewis acidity of tricoordinate silicon cations brings about unusual reactivity in Lewis acid catalysis. The downside of catalysis with strong Lewis acids is, though, that these do have the potential to mediate the formation of protons by various mechanisms, and the thus released Bronsted acid might even outcompete the Lewis acid as the true catalyst. That is an often ignored point. One way of eliminating a hidden proton-catalyzed pathway is to add a proton scavenger. The low-temperature Diels-Alder reactions catalyzed by our ferrocene-stabilized silicon cation are such a case where the possibility of proton catalysis must be meticulously examined. Addition of the common hindered base 2,6-di-tert-butylpyridine resulted, however, in slow decomposition along with formation of the corresponding pyridinium ion. Quantitative deprotonation of the silicon cation was observed with more basic (Mes)3P to yield the phosphonium ion. A deuterium-labeling experiment verified that the proton is abstracted from the ferrocene backbone. A reasonable mechanism of the proton formation is proposed on the basis of quantum-chemical calculations. This is, admittedly, a particular case but suggests that the use of proton scavengers must be carefully scrutinized, as proton formation might be provoked rather than prevented. Proton-catalyzed Diels-Alder reactions are not well-documented in the literature, and a representative survey employing TfOH is included here. The outcome of these catalyses is compared with our silylium ion-catalyzed Diels-Alder reactions, thereby clearly corroborating that hidden Bronsted acid catalysis is not operating with our Lewis acid. Several simple-looking but challenging Diels-Alder reactions with exceptionally rare dienophile/enophile combinations are reported. Another indication is obtained from the chemoselectivity of the catalyses. The silylium ion-catalyzed Diels-Alder reaction is general with regard to the oxidation level of the α,β-unsaturated dienophile (carbonyl and carboxyl), whereas proton catalysis is limited to carbonyl compounds.

Triethylsulfonium bistriflimide as the reaction medium in catalyzed and uncatalyzed cycloaddition [4 + 2]

Triethylsulfonium bistriflimide, [S2.2.2][NTf2], has been tested and compared with other ionic liquids and molecular solvents as a medium in Diels-Alder reaction between cyclopentadiene and dimethyl maleate. Triflates and chlorides of different metals have been combined with [S 2.2.2][NTf2] and the catalytic activity of the systems formed have been determined. The effect of concentration of the catalysts in sulfonium ionic liquid and reactants on the yield and endo:exo ratio has been established. The representative catalyst-Yb(OTf)3?xH 2O in [S2.2.2][NTf2] has been examined in the reaction of cyclopentadiene with various dienophiles. The use of sulfonium ionic liquids permitted recycling the catalysts. For the best four catalytic systems, the products have been isolated.

Enhanced Diels-Alder reactions: on the role of mineral catalysts and microwave irradiation in ionic liquids as recyclable media

This manuscript explores in detail the combined effect of solid supports or microwave irradiation in ionic liquids on a series of Diels-Alder reactions involving 1,3-cyclopentadiene and numerous dienophiles.

Reversal of chemoselectivity in diels-alder reaction with α,β-unsaturated aldehydes and ketones catalyzed by bronsted acid or Lewis Acid

(Chemical Equation Presented) High chemoselectivity was observed in the Diels-Alder reaction of α,β-unsaturated aldehyde and α,β-unsaturated ketone with cyclopentadiene. Using Tf2NH as catalyst, the reaction gave Diels-Alder adduct derived from α,β-unsaturated ketone as a major product. On the other hand, bulky Lewis acid, B(C6F5)3, gave mainly the cycloadduct of α,β-unsaturated aldehyde and cyclopentadiene.

I2 as an efficient catalyst in ionic Diels-Alder reactions of α,β-unsaturated acetals

A variety of protected and unprotected α,β-unsaturated aldehydes react with 1,3-dienes in the presence of I2 to give the corresponding cycloadducts.

Indium trichloride: A useful catalyst for ionic Diels-Alder reactions

Indium trichloride (20 mol%) in nitromethane permits ionic Diels-Alder reaction of a variety of 2,3-olefinic acetals to form the corresponding cycloadducts in good yields with good endo selectivities. (C) 2000 Elsevier Science Ltd.

Studies in Lewis acid and LiClO4 (or Nafion-H) catalysed ionic Diels- Alder reactions of chiral and achiral olefinic acetals respectively

Chiral olefinic acetals derived from crotonaldehyde undergo ionic Diels- Alder reaction giving the corresponding cycloadducts in moderate to good diastereoselectivities. A variety of achiral olefinic acetals react with isoprene and cyclopentadiene to form the cycloadducts in good to excellent yields when catalysed by 4M LiClO4 in nitromethane or by Nafion-H in dichloromethane.

Diels-Alder Reactions in Aqueous Solutions. Enforced Hydrophobic Interactions between Diene and Dienophile

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.