Ethyl Vinyl Ketone Research Articles

Medium effects on the 1,3-dipolar cycloaddition of pyridazinium dicyanomethanide with ethyl vinyl ketone in pure and mixed solvents from QM/MM simulations.

The 1,3-dipolar cycloaddition reaction between pyridazinium dicyanomethanide 1 and ethyl vinyl ketone (EVK) has been reported to be a concerted mechanism based on gas-phase ab initio calculations. Our current investigation of this 1,3-dipolar cycloaddition reaction in water, methanol, acetonitrile, H2O-CH3CN, and CH3OH-CH3CN mixtures using novel two-dimensional potentials of mean force (2-D PMF) calculations coupled to QM/MM simulations predicts an alternative free energy surface that supports a stepwise mechanism. The results for the kinetic effect are uniformly in close accord with experimental data and reflect a trigger point for the exponential rate rise in water-acetonitrile mixture. When methanol replaced water, the rate enhancements are more gradual, and there is no trigger point. Calculations in pure solvents and their mixtures at 25 °C and with pure water and acetonitrile at 37 °C indicate that the secondary bridging H-bonding from the first water molecules is necessary for the exponential rate enhancements, which is strong supported by the experimental results. This work provides new insight into solvent effects on 1,3-dipolar cycloaddition reaction.

Synthesis, Optical Resolution, and Stereochemical Properties of a Rationally Designed Chiral C–N Palladacycle

A novel racemic tertiary amine, 1-(2,5-diisopropylphenyl)-N,N-dimethylethanamine, was synthesized from 2,5-diisopropylbenzaldehyde via a multistep approach in high overall yield. The ortho palladation of this ligand was found to be sensitive to the reaction conditions and the palladating reagents employed. The metal complexation process could thus generate a cyclopalladated complex in high yield, lead to an unexpected N-demethylated amine palladium(II) complex, or both. Both products have been isolated and characterized crystallographically in the solid state and spectroscopically in solution. The racemic cyclopalladated complex could be efficiently resolved via the formation of (S)-prolinato derivatives. The absolute stereochemistries of the resolved diastereomeric complexes were determined by single-crystal X-ray crystallography in the solid state and by 1H–1H rotating frame Overhauser effect (ROESY) NMR spectroscopy in solution. An evaluation of the sterically hindered resolved cyclopalladated units as chiral auxiliaries was conducted in the endo-cycloaddition reaction between 3,4-dimethyl-1-phenylphosphole (DMPP) and ethyl vinyl ketone. The two expected phosphanorbornene adducts were generated with moderate stereoselectivity.

Palladium-promoted asymmetric cycloaddition reaction of arsole via an unusual exo–endo stereochemically controlled method

Asymmetric cycloaddition reaction between 3,4-dimethyl-1-phenylarsole and ethyl vinyl ketone was promoted by the palladium complex containing ortho-metalated (S)-[1-(dimethylamino)ethyl]naphthalene as the chiral auxiliary. The keto group in the resulting arsanorbornene cycloadducts could be located stereospecifically in the endo or exo position by controlling the electronic properties of the organopalladium promoter. In the intermolecular cycloaddition reaction, a pair of separable diastereomeric palladium complexes was obtained in the ratio of 2:1. In the intramolecular process, however, only one As–O bidentate arsanorbornene palladium complex was produced stereoselectively. The arsenic-elimination reaction was readily observed on the corresponding endo- and exo-ketoarsine ligands. The absolute configuration and the coordination property of the enantiomerically pure endo-cycloadduct had been established by single-crystal X-ray analysis.

ChemInform Abstract: Enantioselective Metal/Organo‐Catalyzed Aerobic Oxidative sp3 C—H Olefination of Tertiary Amines Using Molecular Oxygen as the Sole Oxidant.

AbstractN‐Aryltetrahydroisoquinolines are olefinated by acrylaldehyde, methyl or ethyl vinyl ketone, or acrylonitrile in the presence of a copper(II)/quinine catalyst system to give the corresponding 1‐alkenyltetrahydroisoquinolines (22 examples) with up to 99% enantioselectivity.

Dendritic Catalysis in Asymmetric Synthesis

In this review, we have focused our attention on the application of dendrimers as asymmetric catalyst in organic synthesis, which appeared in the literature. Dendrimers have been identified as a promising candidate for catalysis application. The combination of high surface area and high solubility makes dendrimers as useful nanoscale catalysts. The main advantage of the dendritic catalysts is they can be separated from the reaction mixture by simple solvent precipitation and reused for several times with similar catalytic activity. Importance of catalytically active substances like metal salts or organic molecule like pyrrolidinylmethanol thatare attached either to the core or to the periphery of the dendrimers have been highlighted and their applications in important organic reactions such as Baylishillman, Mannich-type, Diels-Alder, Wittig reaction, Michael addition, addition of dialkylzinc to aldehyde, asymmetric epoxide ring opening, asymmetric hydrogenation and asymmetric epoxidation are also presented. Use of dendrimer based salts and chiral compounds in asymmetric syntheses are discussed and the advantages and disadvantages of those catalysts are brought out in this review. Keywords: Dendritic catalyses, Asymmetric syntheses, Organic transformations, Chiral catalysts, residues, boundchiral ligands, Dendrimers, catalysts, pyrrolidinylmethanol, ethylvinyl ketone

Enantioselective Catalytic Diels–Alder Reactions with Enones As Dienophiles

The aqua complexes (SM,RC)-[(η5-C5Me5)M(PROPHOS)(H2O)][SbF6]2 [PROPHOS = (R)-propane-1,2-diylbis(diphenylphosphane); M = Rh (1), Ir (2)] are active catalysts for the asymmetric Diels–Alder reaction between ketones and dienes. At low temperatures, enantioselectivities of up to 89% ee are achieved. The intermediate Lewis acid–dienophile complexes (SM,RC)-[(η5-C5Me5)M(PROPHOS)(MVK)][SbF6]2 (MVK = methyl vinyl ketone; M = Rh (3), Ir (4)) and (SIr,RC)-[(η5-C5Me5)Ir(PROPHOS)(EVK)][SbF6]2 (EVK = ethyl vinyl ketone (5)) have been isolated and characterized by analytical and spectroscopic means, including the determination of the crystal structure of the iridium complexes 4 and 5 by X-ray diffractometric methods. Structural parameters indicate that the dispositions of the coordinated dienophiles are controlled by the CH/π attractive interactions established between a phenyl group of the PROPHOS ligand and the α-vinyl proton of the ketones. Proton NMR parameters indicate that these interactions are maintained in so...

An environmentally benign protocol: catalyst-free Michael addition of aromatic amines to α,β-unsaturated ketones in glycerol

Glycerol was used as a reaction medium as well as promoter for aza-Michael addition of aromatic amines to electronic deficient α,β-unsaturated ketones. Various aromatic amines can react smoothly with chalcone, 2-cyclohexen-1-one, 2-cyclopenten-1-one, and ethyl vinyl ketone to achieve good to excellent yields in the absence of any catalyst.

Synthesis of 2-Propanoyl-5-Norbornene in Pyridinium Ionic Liquids Catalyzed by Yttrium Salts

The use of pyridinium ionic liquids as solvent and catalytic systems based on yttrium salts dissolved in pyridinium ionic liquids for the synthetically important Diels–Alder reaction between cyclopentadiene and ethyl-vinyl ketone was studied. Both chloride and triflate were active catalysts in cycloaddition, strongly improving the reaction rate and stereoselectivity. The catalytic system—1 mol% YCl3/[C4-3-C1py][OTf] (N-butyl-3-methylpyridinium trifluoromethanesulfonate) proved to be stable under recycling conditions.

Generation of Methyl Vinyl Ketone from Oxidation of Levulinic Acid Oxidized by Cupric Oxide Complex

AbstractMethyl vinyl ketone (MVK) is a kind of high‐value chemical which has been widely used in many fields. In this paper, it is formed from oxidation of levulinic acid–a hydrolysis product of biomass. Copper oxide supported on cerium dioxide (CuO/CeO2) and alumina (CuO/Al2O3) were prepared and used for the oxidation of levulinic acid (LA). The oxidants were characterized by means of X‐ray diffraction (XRD), H2‐temperature programmed reduction (H2‐TPR) and atomic force microscope (AFM) techniques. CuO/CeO2 and CuO/Al2O3 show a different behavior with respect to pure CuO. The experiments revealed that CuO/CeO2 and CuO/Al2O3 can oxidize LA and get methyl vinyl ketone [yield of 15.5% detected by head space‐gas chromatograph‐mass spectrometer (HS‐GC‐MS)] under mild reactive conditions, while pure CuO oxidizes LA to produce butanone (MEK).

Aza-Morita–Baylis–Hillman reaction with ion-supported Ph3P

Various N-tosyl arylimines reacted with methyl vinyl ketone and ethyl vinyl ketone in the presence of ion-supported Ph3P A and B to give adducts, N-(2′-methylene-3′-oxo-1′-arylbutyl)-4-methylbenzenesulfonamides and N-(2′-methylene-3′-oxo-1′-arylpentyl)-4-methylbenzenesulfonamides, respectively, in good yields with high purity by simple diethyl ether extraction of the reaction mixture. Moreover, ion-supported Ph3P A and B could be repeatedly used for the same reaction to provide the corresponding adducts while maintaining good yields with high purity.

ChemInform Abstract: Chiral Bifunctional Thiourea—Phosphane Organocatalysts in Asymmetric Allylic Amination of Morita—Baylis—Hillman Acetates.

A series of new chiral bifunctional thiourea-phosphane catalysts was synthesized and successfully applied in the catalytic, asymmetric allylic amination of Morita-Baylis-Hillman (MBH) acetates derived from the methyl vinyl ketone (MVK) or ethyl vinyl ketone (EVK) system, with phthalimide, affording the amination products in up to over 99 % yield and 90 % ee for a wide range of substrates derived from different aromatic aldehydes.

NADPH-dependent Reductases Involved in the Detoxification of Reactive Carbonyls in Plants

Reactive carbonyls, especially α,β-unsaturated carbonyls produced through lipid peroxidation, damage biomolecules such as proteins and nucleotides; elimination of these carbonyls is therefore essential for maintaining cellular homeostasis. In this study, we focused on an NADPH-dependent detoxification of reactive carbonyls in plants and explored the enzyme system involved in this detoxification process. Using acrolein (CH(2) = CHCHO) as a model α,β-unsaturated carbonyl, we purified a predominant NADPH-dependent acrolein-reducing enzyme from cucumber leaves, and we identified the enzyme as an alkenal/one oxidoreductase (AOR) catalyzing reduction of an α,β-unsaturated bond. Cloning of cDNA encoding AORs revealed that cucumber contains two distinct AORs, chloroplastic AOR and cytosolic AOR. Homologs of cucumber AORs were found among various plant species, including Arabidopsis, and we confirmed that a homolog of Arabidopsis (At1g23740) also had AOR activity. Phylogenetic analysis showed that these AORs belong to a novel class of AORs. They preferentially reduced α,β-unsaturated ketones rather than α,β-unsaturated aldehydes. Furthermore, we selected candidates of other classes of enzymes involved in NADPH-dependent reduction of carbonyls based on the bioinformatic information, and we found that an aldo-keto reductase (At2g37770) and aldehyde reductases (At1g54870 and At3g04000) were implicated in the reduction of an aldehyde group of saturated aldehydes and methylglyoxal as well as α,β-unsaturated aldehydes in chloroplasts. These results suggest that different classes of NADPH-dependent reductases cooperatively contribute to the detoxification of reactive carbonyls.

Chiral Bifunctional Thiourea–Phosphane Organocatalysts in Asymmetric Allylic Amination of Morita–Baylis–Hillman Acetates

AbstractA series of new chiral bifunctional thiourea–phosphane catalysts was synthesized and successfully applied in the catalytic, asymmetric allylic amination of Morita–Baylis–Hillman (MBH) acetates derived from the methyl vinyl ketone (MVK) or ethyl vinyl ketone (EVK) system, with phthalimide, affording the amination products in up to over 99 % yield and 90 % ee for a wide range of substrates derived from different aromatic aldehydes.

Atmospheric photodegradation of ethyl vinyl ketone and vinyl propionate initiated by OH radicals

Rate coefficients for the reactions of hydroxyl radicals with ethyl vinyl ketone and vinyl propionate were determined at 298 K and atmospheric pressure. A collapsible chamber with gas chromatography was used to perform relative kinetic determinations. The room temperature rate coefficients (in cm 3 molecule −1 s −1) were: k 1(OH + CH 2 CHC(O)CH 2CH 3) = (2.90 ± 0.79) × 10 −11 and k 2(OH + CH 2 CHOC(O)CH 2CH 3) = (2.46 ± 0.28) × 10 −11. This is the first kinetic study of title reactions under atmospheric conditions. The kinetic data were compared with previous literature values, used to calculate atmospheric lifetimes and correlated with the ionization potential of the unsaturated compounds.

Tandem Michael Addition/Aldol Reaction of Allenic Ketones with Alkyl Vinyl Ketones: Versatile Synthesis of 2‐Alkynyl 1,5‐Diketones, 4‐Alkynyl‐3‐hydroxycyclohexanones and 4‐Alkynylcyclohexenones

AbstractThe reactivity of alkynylenolate was investigated in the reactions of allenic ketones and vinyl ketones. We found that different products could be obtained under different conditions. The tetrabutylammonium fluoride (TBAF)‐mediated Michael addition of allenic ketones to vinyl ketones gave 2‐alkynyl 1,5‐diketones as the product. Under stronger basic conditions, a tandem Michael addition/aldol reaction of the two starting materials occurred in one pot, and 4‐alkynyl‐3‐hydroxycyclohexanone could be isolated at low temperature, whereas 4‐alkynylcyclohexenones was obtained at room temperature. It should be noted that only one diastereoisomer of 4‐alkynyl‐3‐hydroxycyclohexanone was isolated from the reaction even when ethyl vinyl ketone was used as the Michael acceptor, as determined by 1H and 13C NMR spectroscopy. The configurations of the diastereoisomers were confirmed by NOESY spectroscopy.

ChemInform Abstract: Synthetic Studies on Diterpenoid Quinones with Interleukin-1 Inhibitory Activity. Total Synthesis of (.+-.)- and (+)-Triptoquinone A.

An efficient first total synthesis of (±)- and (+)-triptoquinone A (1), a novel diterpenoid quinone with significant inhibitory activity against interleukin-1 releases, has been completed. Birch reduction of tricyclic enone (±)-7, prepared from known 6-methoxy-2-isopropyl-1-naphthol (22), which is readily available in large quantities, was followed by immediate enolate trapping to provide silyl enol ether (±)-30. Compound 30 was converted into carboxylic acid (±)-4 via the corresponding enol triflate (±)-31 either by sequential palladium-catalyzed carbonylation and oxidation or by direct carboxylation. The total synthesis of (±)-1 was completed by oxidation of (±)-4 with CAN in 12 steps from 22 in 19% overall yield at best. A second, enantioselective total synthesis of (+)-1 was accomplished via (+)-7, which was prepared by (-)-N-[4-(trifluoromethyl)benzyl]cinchonidium bromide(33) catalyzed asymmetric Michael reaction of 6 with ethyl vinyl ketone and a subsequent aldol condensation

Diels–Alder reaction of α-tropolone and electron-deficient dienophiles prompted by Et 3N or silica gel: a new synthetic method of highly functionalized homobarrelenone derivatives

A Diels–Alder reaction of α-tropolone and electron-deficient dienophiles prompted by Et 3N or silica gel was performed. Reaction with the highly reactive dienophile, N-methylmaleimide, proceeded smoothly in the presence of Et 3N or silica gel to yield adducts as a mixture of endo and exo isomers. Both catalysts accelerated endo/ exo isomerization of the product, and detailed examination of the reaction using hinokitiol and N-methylmaleimide revealed that isomerization proceeds via an intramolecular path without retro Diels–Alder reaction. Successful cycloaddition reactions were established with six other dienophiles: acrylonitrile, methyl acrylate, ethyl vinyl ketone, dimethyl fumalate, dimethyl malate, and dimethyl acetylenedicarboxylate, and the corresponding adducts were obtained in good to moderate yields.

Photooxidation of Leaf-Wound Oxygenated Compounds, 1-Penten-3-ol, (Z)-3-Hexen-1-ol, and 1-Penten-3-one, Initiated by OH Radicals and Sunlight

An evaluation of the environmental impact of stressed-induced compounds, 1-penten-3-ol,(Z)-3-hexen-1-ol, and 1-penten-3-one (ethyl vinyl ketone, EVK), is presented in this paper. The removal processes considered here are the gas-phase reactions with hydroxyl (OH) radicals and photolysis in the actinic region (above 290 nm). The wavelength dependence of the gas-phase absorption cross-sections (sigma(lamda)) was measured by UV-visible spectroscopy (lamda = 200-390 nm). The kinetic study of the OH-reaction with pentenyl compounds has been performed as a function of temperature (T = 263-353 K) for the first time. The resulting Arrhenius expressions for the T-dependence of the OH-rate coefficient, k(OH) (in cm3 molecule(-1) s(-1) and uncertainties of +/-sigma), were (7.7 +/- 0.8) x 10(-12) exp{(606 +/- 30)/7} for 1-penten-3-ol and (4.4 +/- 1.4) x 10(-12) exp{(507 +/- 90)/7} for EVK, respectively. k(OH) for (Z)-3-hexen-1-ol is reported at 298 K. The experimental evidence shows that the major tropospheric removal of pentenyl compounds is the gas-phase reaction with OH radicals. However, O3 and NO3 radicals may compete with OH radicals as tropospheric sinks of (Z)-3-hexen-1-ol. Photolysis of these compounds is expected to be of minor importance in the troposphere.

Bifunctional chiral phosphine-containing Lewis base catalyzed asymmetric Morita–Baylis–Hillman reaction of aldehydes with activated alkenes

A series of novel bifunctional chiral phosphine-containing Lewis bases were synthesized and successfully applied to the asymmetric Morita–Baylis–Hillman reaction of aldehydes with methyl vinyl ketone (MVK) and ethyl vinyl ketone (EVK) to give the corresponding adducts in moderate yields and enantioselectivities under mild reaction conditions.

Rhodium-Catalyzed Reductive Aldol Reaction of Vinyl Ketones

The authors report the first enantio­selective reductive aldol coupling of vinyl ketones, which were achieved through the design of a new class of TADDOL-like phosphonite ligands (AP I - AP IV). Hydrogenation of commercially available methyl vinyl ketone or ethyl vinyl ketone in the presence of aldehydes using cationic rhodium catalysts modified by chiral phosphonite ligands produces aldol adducts with excellent control of relative and absolute stereochemistry.