Showing papers on "Methyl vinyl ketone published in 2011"
TL;DR: A novel high yielding and highly enantioselective chiral calcium VAPOL phosphate-catalyzed chlorination of 3-substituted oxindoles with N-chlorosuccinimide (NCS) is disclosed.
Abstract: We disclose a novel high yielding and highly enantioselective chiral calcium VAPOL phosphate-catalyzed chlorination of 3-substituted oxindoles with N-chlorosuccinimide (NCS) The reaction conditions are also shown to be effective for the catalytic enantioselective Michael addition of 3-aryloxindoles to methyl vinyl ketone
152 citations
TL;DR: In this article, the first-generation and total production yields of glyoxal, methyl glyoxalin, glycolaldehyde, and hydroxyacetone from the oxidation of isoprene, methyl vinyl ketone (MVK), and methacrolein (MACR) with OH under high NO_x conditions were presented.
Abstract: We present first-generation and total production yields of glyoxal, methylglyoxal, glycolaldehyde, and hydroxyacetone from the oxidation of isoprene, methyl vinyl ketone (MVK), and methacrolein (MACR) with OH under high NO_x conditions. Several of these first-generation yields are not included in commonly used chemical mechanisms, such as the Leeds Master Chemical Mechanism (MCM) v. 3.2. The first-generation yield of glyoxal from isoprene was determined to be 2.1 (±0.6)%. Inclusion of first-generation production of glyoxal, glycolaldehyde and hydroxyacetone from isoprene greatly improves performance of an MCM based model during the initial part of the experiments. In order to further improve performance of the MCM based model, higher generation glyoxal production was reduced by lowering the first-generation yield of glyoxal from C5 hydroxycarbonyls. The results suggest that glyoxal production from reaction of OH with isoprene under high NO_x conditions can be approximated by inclusion of a first-generation production term together with secondary production only via glycolaldehyde. Analogously, methylglyoxal production can be approximated by a first-generation production term from isoprene, and secondary production via MVK, MACR and hydroxyacetone. The first-generation yields reported here correspond to less than 5% of the total oxidized yield from isoprene and thus only have a small effect on the fate of isoprene. However, due to the abundance of isoprene, the combination of first-generation yields and reduced higher generation production of glyoxal from C5 hydroxycarbonyls is important for models that include the production of the small organic molecules from isoprene.
105 citations
TL;DR: The results reinforced the observations by Yamamoto and Knight that doubly activated Michael acceptors were required to capture the relatively unreactive amide anion and reasoned that increased nucleophilicity should therefore be possible with an anionic Pd complex instead.
Abstract: route to vinyl epoxides and vinyl aziridines via chiral sulfur ylides, we were keen to develop their potential in synthesis further. It had been reported that palladium-catalyzed reactions of vinyl epoxides and aziridines with doubly activated Michael acceptors gave tetrahydrofurans and pyrrolidines in good yield but usually with poor stereocontrol. However, related reactions with singly activated Michael acceptors were not effective. Nevertheless, we recognized that if we could find a way of coercing vinyl aziridines to react with singly activated enones/acrylates, and we were able to control stereochemistry in the annulation process, then we could potentially utilize this methodology in synthesis. Herein, we describe our success in simultaneously meeting these two significant challenges and also describe its application in a formal synthesis of ( )-a-kainic acid 1. Our initial efforts at promoting reaction between vinyl aziridine 2a and methyl vinyl ketone (MVK, A) using [Pd2(dba)3·CHCl3], (p-FC6H5)3P in THF (conditions employed by Yamamoto), however, were fruitless—we only observed decomposition. Using trimethylsilyl-substituted trans vinyl aziridine 2e, we now observed isomerization to a mixture of trans/cis aziridines (1:20). With this substrate, clearly the Pd was performing its role in generating the p-allyl palladium complex as this resulted in isomerization of the vinyl aziridine. However, the amide anion that was generated did not react with the enone. This result reinforced the observations by Yamamoto and Knight that doubly activated Michael acceptors were required to capture the relatively unreactive amide anion. We reasoned that ion pairing of the amide anion with the cationic Pd complex might compromise its reactivity, and that increased nucleophilicity should therefore be possible with an anionic Pd complex instead (Scheme 2).
105 citations
TL;DR: In this article, the enthalpies of reaction have been computed for the conjugate additions of MeSH to six α,β-unsaturated ketones, and substituent effects on the activation energies for the rate-determining step of the thiol addition (reaction of the enone with MeS−) were also computed.
Abstract: CBS-QB3 enthalpies of reaction have been computed for the conjugate additions of MeSH to six α,β-unsaturated ketones. Compared with addition to methyl vinyl ketone, the reaction becomes 1–3 kcal mol–1 less exothermic when an α-Me, β-Me, or β-Ph substituent is present on the C═C bond. The lower exothermicity for the substituted enones occurs because the substituted reactant is stabilized more by hyperconjugation or conjugation than the product is stabilized by branching. Substituent effects on the activation energies for the rate-determining step of the thiol addition (reaction of the enone with MeS–) were also computed. Loss of reactant stabilization, and not steric hindrance, is the main factor responsible for controlling the relative activation energies in the gas phase. The substituent effects are further magnified in solution; in water (simulated by CPCM calculations), the addition of MeS– to an enone is disfavored by 2–6 kcal mol–1 when one or two methyl groups are present on the C═C bond (ΔΔG⧧). The...
82 citations
TL;DR: In this paper, a series of chiral bifunctional thiourea-phosphane catalysts were synthesized and successfully applied in the catalytic, asymmetric allylic amination of MBH (Morita-Baylis-Hillman) acetates derived from the methyl vinyl ketone (MVK), with phthalimide, affording the amination products in up to over 99 % yield and 90 % ee.
73 citations
TL;DR: In this paper, the authors analyzed the aqueous OH-initiated oxidation of isoprene and its reaction products including carbonyl compounds and organic acids, regarding the acidity and temperature as in-cloudy conditions.
Abstract: . Aqueous phase chemical processes of organic compounds in the atmosphere have received increasing attention, partly due to their potential contribution to the formation of secondary organic aerosol (SOA). Here, we analyzed the aqueous OH-initiated oxidation of isoprene and its reaction products including carbonyl compounds and organic acids, regarding the acidity and temperature as in-cloudy conditions. We also performed a laboratory simulation to improve our understanding of the kinetics and mechanisms for the products of aqueous isoprene oxidation that are significant precursors of SOA; these included methacrolein (MACR), methyl vinyl ketone (MVK), methyl glyoxal (MG), and glyoxal (GL). We used a novel chemical titration method to monitor the concentration of isoprene in the aqueous phase. We used a box model to interpret the mechanistic differences between aqueous and gas phase OH radical-initiated isoprene oxidations. Our results were the first demonstration of the rate constant for the reaction between isoprene and OH radical in water, 1.2 ± 0.4) × 1010 M−1 s−1 at 283 K. Molar yields were determined based on consumed isoprene. Of note, the ratio of the yields of MVK (24.1 ± 0.8 %) to MACR (10.9 ± 1.1%) in the aqueous phase isoprene oxidation was approximately double that observed for the corresponding gas phase reaction. We hypothesized that this might be explained by a water-induced enhancement in the self-reaction of a hydroxy isoprene peroxyl radical (HOCH2C(CH3)(O2)CH = CH2) produced in the aqueous reaction. The observed yields for MG and GL were 11.4 ± 0.3 % and 3.8 ± 0.1 %, respectively. Model simulations indicated that several potential pathways may contribute to the formation of MG and GL. Finally, oxalic acid increased steadily throughout the course of the study, even after isoprene was consumed completely. The observed yield of oxalic acid was 26.2 ± 0.8 % at 6 h. The observed carbon balance accounted for ~50 % of the consumed isoprene. The presence of high-molecular-weight compounds may have accounted for a large portion of the missing carbons, but they were not quantified in this study. In summary, our work has provided experimental evidence that the availably abundant water could affect the distribution of oxygenated organic compounds produced in the oxidation of volatile organic compounds.
57 citations
TL;DR: Interestingly, aza- Michael addition reactions of secondary amines to acrylonitrile have been also efficiently catalyzed, observing with diethylamine the most remarkable differences between the enzyme-mediated reaction and the one in the absence of catalyst.
Abstract: Commercially available protease from Bacillus licheniformis has been used in different non-conventional biotransformations showing remarkable activity values. The promiscuous behaviour of this enzyme used in the cross-linked enzyme aggregates immobilized form (Alcalase-CLEA®), has been successfully demonstrated for the first time in CC bond formation processes such as aldol, Henry and Mannich reactions. On the other hand, the Bayllis–Hillman reaction between 4-nitrobenzaldehyde and methyl vinyl ketone occurred through unspecific catalysis. Interestingly, aza- Michael addition reactions of secondary amines (diethylamine, piperidine and pyrrolidine) to acrylonitrile have been also efficiently catalyzed, observing with diethylamine the most remarkable differences between the enzyme-mediated reaction and the one in the absence of catalyst. Higher reactivities were attained with pyrrolidine demonstrating the versatility of hydrolases in organic synthesis.
48 citations
TL;DR: The cationic nickel pincers 3 are found to be effective catalysts for the Michael addition of ethyl 2-cyanopropionate to methyl vinyl ketone in the presence of i-Pr(2)NEt base with a catalyst loading of 5 mol% even at -78 °C, producing the adduct in >99% yield after 24 h albeit with no ee.
Abstract: Chiral 1,3-bis(2′-imidazolinyl)benzenes 1a–e easily undergo direct nickelation at the C2 position of the central benzene ringvia the C–H bond activation in the reaction with anhydrous NiCl2 giving neutral NCN pincer nickel(II) complexes 2a–e in 40–87% yields. Treatment of the nickel pincers 2a or 2c with AgBF4 in CH3CN–CH2Cl2 afforded the cationic nickel pincers 3a or 3c in good yields. All the complexes were characterized by elemental analysis, 1H, 13C NMR, and IR spectra. Molecular structures of the neutral complexes 2a, 2b and 2c as well as the cationic complex 3c have been determined by X-ray single-crystal diffraction. The cationic nickel pincers 3 are found to be effective catalysts for the Michael addition of ethyl 2-cyanopropionate to methyl vinyl ketone in the presence of i-Pr2NEt base with a catalyst loading of 5 mol% even at −78 °C, producing the adduct in >99% yield after 24 h albeit with no ee.
35 citations
TL;DR: In this paper, a chirped-pulse Fourier transform microwave spectrometer was used to record the rotational spectrum of methyl vinyl ketone (MVK, 3-butene-2-one).
25 citations
TL;DR: The use of high pressure as the activating method of the Diels-Alder reactions allows the efficient and endodiastereoselective generation of a series of cis-cyclohexenyl-benzene cycloadducts, which are selectively converted into their trans-epimers.
Abstract: Diels–Alder reactions of a range of 1-(alkoxy/alkyl-substituted phenyl)buta-1,3-dienes with methyl vinyl ketone and methyl acrylate carried out in ethanol as the reaction medium under 9 kbar pressure were investigated. The use of high pressure as the activating method of the Diels–Alder reactions allows the efficient and endodiastereoselective generation of a series of cis-cyclohexenyl-benzene cycloadducts, which are selectively converted into their trans-epimers. The cis-cyclohexenyl-benzenes and trans-cyclohexenyl-benzenes produced are useful precursors for accessing substituted privileged cis-6a,7,8,10a-tetrahydro-6H-benzo[c]chromene and trans-6a,7,8,10a-tetrahydro-6H-benzo[c]chromene skeletons. The total syntheses of Δ9-cis-tetrahydrocannabinol (THC) and Δ9-trans-THC, through the use of selected Diels–Alder adducts, are described. Finally, a route for obtaining Δ9-trans-THC in both enantiomeric pure forms based on the (S)-(−)-1-amino-2-(methoxymethyl)pyrrolidine (SAMP)-hydrazone method is also reported.
24 citations
TL;DR: In this article, cycloaurated gold(III) complexes derived from cyclo-aurated iminophosphorane, triphenylphosphine sulfide or selenide, or pyridylsulfonamide ligands have been assessed for their catalytic activity in the addition of 2-methylfuran to methyl vinyl ketone.
Abstract: Cycloaurated gold(III) complexes derived from cycloaurated iminophosphorane, triphenylphosphine sulfide or selenide, or pyridylsulfonamide ligands have been assessed for their catalytic activity in the addition of 2-methylfuran to methyl vinyl ketone. Addition of AgBF4 was generally needed for high activity, although those with coordinated atoms of high trans influence showed some activity in the absence of added Ag+. Copyright © 2011 John Wiley & Sons, Ltd.
TL;DR: In this article, a series of mixed-cation organoclays, containing both Fe3+ and choline+ cations, were prepared using montmorillonite and tested for catalytic activity in three Fe3-mediated reactions: the oxidative coupling of 2-naphthol, coupling of anthrone and a Lewis acid catalysed indole conjugate addition.
TL;DR: In this paper, a photo-scissible poly(p-hydroxystyrene) derivatives with ketone groups was obtained by radical copolymerization of O-protected poly(HSt) and 2,2-diphenyl-4methylene-1,3-dioxorane (DPMD).
Abstract: INTRODUCTION Poly(p-hydroxystyrene) [poly(HSt)] and its derivatives are well known as functional polymers and have been applied variously to photoresist materials, composites, a physical gel, and a pH responsive material. Therefore, it is expected that endowing poly(HSt) derivatives with photo-scissibility will lead to the development of novel photosensitive functional materials. Recently, we have succeeded in the synthesis of photo-scissible poly(HSt) derivatives by the incorporation of ketone groups into the main chain, which was conducted by radical copolymerization of O-protected p-hydroxystyrene (ROSt) and 2,2-diphenyl-4methylene-1,3-dioxorane (DPMD) (Scheme 1). DPMD can undergo the radical ring-opening polymerization to afford the corresponding polyketone, which can be regarded as the copolymers of ethylene and carbon monoxide. Therefore, radical copolymerization of ROSt with DPMD and subsequent removal of protective groups gave the poly(HSt) derivatives having ketone groups in the main chain. The obtained poly(HSt) derivatives with ketone groups showed good photoscissibility based on Norrish-type reactions.
TL;DR: In this article, oxo esters with pyrrolidine and tetrahydrofuran rings were converted into optically active isobenzofuran and isoindole derivatives.
Abstract: Oxo esters with pyrrolidine and tetrahydrofuran rings were converted into optically active isobenzofuran and isoindole derivatives. The key step of the sequence was a copper-catalyzed asymmetric Michael reaction with methyl vinyl ketone and en-amines prepared from the oxo esters and L-valine diethylamide. The chiral auxiliary was cleaved from the products during workup and 1,5-diketones with a quaternary stereocenter are obtained with 97-99% ee. Subsequent annulation reactions were achieved in two steps via the intermediate aldol products.
TL;DR: In this article, the authors describe the synthesis and the catalysis of new recyclable polymer-supported Pd catalysts, applicable to Mizoroki-Heck coupling.
Abstract: This manuscript describes the synthesis and the catalysis of new recyclable polymer-supported Pd catalysts, applicable to Mizoroki–Heck coupling The prepolymers bearing azine structures as the ligation groups were prepared via the reaction of poly(methyl vinyl ketone) and hydrazine to produce a polymer bearing hydrazone moieties followed by its reaction with aromatic aldehydes The activities of the catalysts were higher as the decrease of the electron densities of the azine moieties
TL;DR: In this paper, the efficiency of poly(N-vinylimidazole) as the basic recyclable catalyst for the addition of CH-acids to acrylonitrile, methyl acrylate, methyl vinyl ketone and methyl vinyl sulfone in water at ambient temperature was studied.
Abstract: Efficiency of poly(N-vinylimidazole) as the basic recyclable catalyst for the Michael addition of CH-acids to acrylonitrile, methyl acrylate, methyl vinyl ketone and methyl vinyl sulfone in water at ambient temperature was studied. In these reactions, formation of both 1: 1 and 1: 2 adducts is possible.
TL;DR: In this paper, X-ray crystallographic, computer modelling and NMR techniques have been used to elucidate questions concerning configurational preferences, reaction pathways and the apparent difference in susceptibility towards aza-Michael reactions exhibited by methyl acrylate and methyl vinyl ketone (MVK) derived Baylis-Hillman substrates.
Patent•
07 Jan 2011TL;DR: In this article, a method for converting levulinic acid to methyl vinyl ketone is described, which includes the steps of reacting an aqueous solution of a solution of the acid over an acid catalyst, at a temperature of from room temperature to about 1100 K.
Abstract: A method for converting levulinic acid to methyl vinyl ketone is described. The method includes the steps of reacting an aqueous solution of levulinic acid, over an acid catalyst, at a temperature of from room temperature to about 1100 K. Methyl vinyl ketone is thereby formed.
Journal Article•
TL;DR: In this article, a series of amide-based acidic ionic liquids, including N-methyl-2-pyrrolidonium dihydrogen phosphate (NMPH) and caprolactam dihy-drogen phosphate(NHCH) were synthesized and characterized.
01 Jan 2011
TL;DR: In this paper, secondary organic aerosol (SOA) formation from the reaction of isoprene with OH radical was studied using smog chamber, and gaseous products were determined by proton-transfer-reaction mass spectrometer (PTR-MS) while SOA concentration and size distribution were determined using EEPS3090.
Abstract: Using smog chamber,Secondary organic aerosol (SOA) formation from the reaction of isoprene with OH radical was studied.Gaseous products were determined by proton-transfer-reaction mass spectrometer (PTR-MS) while SOA concentration and size distribution were determined by EEPS3090.The dominating gaseous products were methacrolein (MAC)/methyl vinyl ketone (MVK),acetaldehyde,formaldehyde,methanol,formic acid/ethanol,glycollic aldehyde,methylglyoxal,acetone/propionaldehyde and so on.The highest production of MAC/MVK and acetaldehyde were 13.78% 37.72% and 5.38% 9.34% (based on C).SOA production and its mean size increased with increasing reacted isoprene.When the gas phase products were stable,the SOA yields were in the range of 5.6% 11.7% and the particle sizes were from 22 nm to 165 nm.
TL;DR: In this paper, the Baylis-Hillman reaction conditions were used to obtain 8-formyl-7-hydroxy chromones with methyl vinyl ketone and acrylonitrile.
Abstract: Abstract Condensation of 8-formyl-7-hydroxy chromones 2a–e with methyl vinyl ketone and acrylonitrile in the presence of diazabicyclo[2.2.2]octane (DABCO) under Baylis-Hillman reaction conditions afforded 9-cyano/acetyl-substituted pyrano[2,3-f]chromones 3a–e and 4a–e.
Journal Article•
TL;DR: In this article, a 1 H NMR spectroscopy-based kinetic analysis of the Baylis-Hillman reaction with methyl vinyl ketone (MVK) is presented.
Abstract: DABCO-catalyzed reaction of 3-methoxy-2-nitrobenzaldehyde with methyl vinyl ketone (MVK) affords a mixture of products, comprising the ‘normal’ Baylis-Hillman adduct, the MVK dimer and a pair of diastereomeric bis-(MVK) Baylis-Hillman adducts. 1 H NMR spectroscopy-based kinetic studies have provided clear insights into the competing pathways and product distribution in this complex reaction. Keywords: Baylis-Hillman reaction, mechanism, kinetics, 1 H NMR spectroscopic analysis, bis-(MVK)Baylis-Hillman products
TL;DR: The reaction is best catalyzed by the (diphenylphosphino)(cyclohexyl)-phenylthiourea and is applied to the various acrylates (II), (IV), acrolein (VIIIa) and methyl vinyl ketone (VIIb).
Abstract: The reaction is best catalyzed by the (diphenylphosphino)(cyclohexyl)-phenylthiourea and is applied to the various acrylates (II), (IV), acrolein (VIIIa) and methyl vinyl ketone (VIIIb).
TL;DR: A variety of aromatic and aliphatic nitroalkenes or nitrodienes undergoes heterocoupling reaction with methyl vinyl ketone (II) or acrylate (IV) in the presence of LiCl and imidazole as discussed by the authors.
Abstract: A variety of aromatic and aliphatic nitroalkenes or nitrodienes undergoes heterocoupling reaction with methyl vinyl ketone (II) or acrylate (IV) in the presence of LiCl and imidazole.
TL;DR: In this paper, a series of chiral bifunctional thiourea-phosphane catalysts were synthesized and successfully applied in the catalytic, asymmetric allylic amination of MBH (Morita-Baylis-Hillman) acetates derived from the methyl vinyl ketone (MVK), with phthalimide, affording the amination products in up to over 99 % yield and 90 % ee.
Abstract: 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.