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Methyl Vinyl Ketone (methyl + vinyl_ketone)
Selected AbstractsGold(III) Chloride-Catalyzed Addition Reactions of Electron-Rich Arenes to Methyl Vinyl KetoneADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11 2003Gerald Dyker Abstract For the reaction of ,,,-unsaturated ketones with electron-rich arenes catalyzed by gold(III) chloride both, a Friedel,Crafts-type mechanism and an initial metallation, are evaluated. Gold(III) chloride has proven to be an efficient catalyst under very moderate reaction conditions, however, in the case of sterically demanding products HBF4 turned out to be the superior catalyst. [source] ChemInform Abstract: Aza-Baylis,Hillman Reaction of Salicyl N-Tosylimines with Methyl Vinyl Ketone, Ethyl Vinyl Ketone or Phenyl Vinyl Ketone.CHEMINFORM, Issue 5 2008Ming-Juan Qi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Synthesis of the Thioamide Derivatives of Methyl Vinyl Ketone and Their Cyclization to 2,3-Dihydro-4H-thiopyran-4-ones.CHEMINFORM, Issue 45 2006L. Gros Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Baylis,Hillman Reactions of N-Arylidenediphenylphosphinamides with Methyl Vinyl Ketone, Methyl Acrylate, and Acrylonitrile.CHEMINFORM, Issue 39 2002Min Shi Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Computational Studies on the BF3 -Catalyzed Cycloaddition of Furan with Methyl Vinyl Ketone: A New Look at Lewis Acid Catalysis.CHEMINFORM, Issue 4 2001Martin Avalos Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] A Nearly Planar Stannene with a Reactive Tin,Carbon Double BondEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2008Abdoul Fatah Abstract Bis(2,4,6-triisopropylphenyl)-2,7-di- tert -butylfluorenylidenestannane, Tip2Sn=CR2, an isolable stannene that displays a deep-purple colour, was synthesized by dehydrofluorination of the corresponding fluorostannane by tert -butyllithium. It exhibits the shortest Sn=C distance [2.003(5) Å] and the slightest twisting around this unsaturation (10°) among the known stannenes. Its reaction with benzaldehyde according to a [2+2] cycloaddition and that with ,-ethylenic aldehydes and ketones such as crotonaldehyde and methyl vinyl ketone by a [2+4] cycloaddition proceeded in near-quantitative yield. With acetone, an ene reaction occurred. The four-membered ring 1,2-oxastannacyclobutane obtained with benzaldehyde underwent a ring expansion with a second molecule of benzaldehyde to afford the six-membered ring dioxastannacyclohexane.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Straightforward Strategy for the Stereoselective Synthesis of Spiro-Fused (C-5)Isoxazolino- or (C-3)Pyrazolino-(C-3)quinolin-2-ones from Baylis,Hillman Adducts by 1,3-Dipolar Cycloaddition and Reductive Cyclization,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 32 2008Virender Singh Abstract A straightforward and general approach for the stereoselective synthesis of spiro-fused (C-5)isoxazolino- or (C-3)pyrazolino-(C-3)quinolin-2-ones from the adducts offorded from the Baylis,Hillman reaction of 2-nitrobenzaldehyde and ethyl acrylate by sequential 1,3-dipolar cycloaddition and reductive cyclization is presented. It was found that the reductive cyclization of the isoxazoline derivatives proceeded efficiently in the presence of In/HCl, whereas similar reductions of pyrazolines gave better yields when carried out in the presence of an Fe/AcOH mixture. However, similar attempts employing the Baylis,Hillman adduct of 2-nitrobenzaldehyde and methyl vinyl ketone did not yield the desired compounds.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Regioselective Spiroannulations of ,-Acetyl LactonesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2003Jens Christoffers Abstract Monocyclic spiroannulation precursors 3a,c were obtained by Michael reactions of ,-acetyl lactones 6a,c with methyl vinyl ketone (7). The selective formation of either regioisomer of both ,-oxo (5a,c) and ,-oxo (4a,c) lactones from 3a,c was achieved by varying the reaction conditions. The ,-oxo lactones 4a,c were obtained under basic (buffered) conditions in a pyrrolidine/AcOH system. Under acidic conditions, the annulation reaction afforded ,-oxo lactones 5a,c. Byproducts 8b,c were identified to be the decomposition products of ,-oxo lactones 5b and 5c by comparison with the spectra of the alcohols 10b,c derived directly from ,-oxo lactones 4b and 4c by saponification/decarboxylation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Rational Color Tuning and Luminescent Properties of Functionalized Boron-Containing 2-Pyridyl Pyrrolide Complexes,ADVANCED FUNCTIONAL MATERIALS, Issue 4 2005H.-Y. Chen Abstract Three systematically functionalized pyrrolide ligands were prepared via the coupling of methyl vinyl ketone and the respective carbaldehyde reagents, followed by treatment of the pre-formed dicarbonyl compounds with (NH4)2CO3 in order to generate the required pyrrole fragment. These ligands readily reacted with the boron reagent BPh3 to afford the complexes [(pyro)BPh2] (2a), [(noro)BPh2] (2b), and [(xaro)BPh2] (2c), where (pyro)H, (noro)H, and (xaro)H represents the 2-pyridyl, 2-quinolinyl, and 2-quinoxalinyl pyrrole groups, respectively. Complexes 2a,2c give stable solutions in air, and show strong photoluminescence with emission peak maxima located at 490,nm, 510,nm, and 575,nm, respectively. Calculations based upon time-dependent density function theory (TDDFT) show that the S1 state in these complexes is attributed to an allowed (,-symmetry),,,,* (,-symmetry) transition located at the chelating pyrrolide moieties. Electroluminescence (EL) devices based on 2c were fabricated. The EL emission from 2c as the host-emitter, with the emission peak maximum shifted to 580,nm, was observed when BCP was used as the hole blocking material. This device produces saturated red-orange light-emission at an onset voltage of 8,V and a maximum brightness of 5000,cd,m,2 at a driving voltage of 15,V; the external quantum yield is estimated to be 0.5,%. [source] Rate coefficients and mechanisms of the reaction of cl-atoms with a series of unsaturated hydrocarbons under atmospheric conditionsINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 8 2003John J. Orlando Rate coefficients and/or mechanistic information are provided for the reaction of Cl-atoms with a number of unsaturated species, including isoprene, methacrolein (MACR), methyl vinyl ketone (MVK), 1,3-butadiene, trans -2-butene, and 1-butene. The following Cl-atom rate coefficients were obtained at 298 K near 1 atm total pressure: k(isoprene) = (4.3 ± 0.6) × 10,10cm3 molecule,1 s,1 (independent of pressure from 6.2 to 760 Torr); k(MVK) = (2.2 ± 0.3) × 10,10 cm3 molecule,1 s,1; k(MACR) = (2.4 ± 0.3) × 10,10 cm3 molecule,1 s,1; k(trans -2-butene) = (4.0 ± 0.5) × 10,10 cm3 molecule,1 s,1; k(1-butene) = (3.0 ± 0.4) × 10,10 cm3 molecule,1 s,1. Products observed in the Cl-atom-initiated oxidation of the unsaturated species at 298 K in 1 atm air are as follows (with % molar yields in parentheses): CH2O (9.5 ± 1.0%), HCOCl (5.1 ± 0.7%), and 1-chloro-3-methyl-3-buten-2-one (CMBO, not quantified) from isoprene; chloroacetaldehyde (75 ± 8%), CO2 (58 ± 5%), CH2O (47 ± 7%), CH3OH (8%), HCOCl (7 ± 1%), and peracetic acid (6%) from MVK; CO (52 ± 4%), chloroacetone (42 ± 5%), CO2 (23 ± 2%), CH2O (18 ± 2%), and HCOCl (5%) from MACR; CH2O (7 ± 1%), HCOCl (3%), acrolein (,3%), and 4-chlorocrotonaldehyde (CCA, not quantified) from 1,3-butadiene; CH3CHO (22 ± 3%), CO2 (13 ± 2%), 3-chloro-2-butanone (13 ± 4%), CH2O (7.6 ± 1.1%), and CH3OH (1.8 ± 0.6%) from trans -2-butene; and chloroacetaldehyde (20 ± 3%), CH2O (7 ± 1%), CO2 (4 ± 1%), and HCOCl (4 ± 1%) from 1-butene. Product yields from both trans -2-butene and 1-butene were found to be O2 -dependent. In the case of trans -2-butene, the observed O2 -dependence is the result of a competition between unimolecular decomposition of the CH3CH(Cl)CH(O,)CH3 radical and its reaction with O2, with kdecomp/kO2 = (1.6 ± 0.4) × 1019 molecule cm,3. The activation energy for decomposition is estimated at 11.5 ± 1.5 kcal mol,1. The variation of the product yields with O2 in the case of 1-butene results from similar competitive reaction pathways for the two ,-chlorobutoxy radicals involved in the oxidation, ClCH2CH(O,)CH2CH3 and ,OCH2CHClCH2CH3. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 334,353, 2003 [source] Enantioselective Trifunctional Organocatalysts for Rate- Enhanced Aza-Morita,Baylis,Hillman Reactions at Room TemperatureADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009Jean-Marc Garnier Abstract A Brønsted acid-activated trifunctional organocatalyst, based on the BINAP scaffold, was used for the first time to catalyze aza-Morita-Baylis,Hillman reactions between N -tosylimines and methyl vinyl ketone with fast reaction rates and good enantioselectivity at room temperature. This trifunctional catalyst, containing a Lewis base, a Brønsted base, and a Brønsted acid, required acid activation to confer its enantioselectivity and rate improvement for both electron-rich and electron-deficient imine substrates. The role of the amino Lewis base of 1a was investigated and found to be the activity switch in response to an acid additive. The counterion of the acid additive was found to influence not only the excess ratio but also the sense of asymmetric induction. [source] Dendritic Chiral Phosphine Lewis Bases-Catalyzed Asymmetric Aza-Morita,Baylis,Hillman Reaction of N -Sulfonated Imines with Activated OlefinsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2008Ying-hao Liu Abstract A series of polyether dendritic chiral phosphine Lewis bases was synthesized, and successfully applied to the asymmetric aza-Morita,Baylis,Hillman reaction of N -sulfonated imines (N -arylmethylidene-4-methylbenzenesulfonamides) with methyl vinyl ketone (MVK), ethyl vinyl ketone (EVK), and acrolein to give the adducts in good to excellent yields along with up to 97,% ee, which are more effective than our previously reported original chiral phosphine Lewis bases. In addition, the dendrimer-supported chiral phosphine Lewis bases can be easily recovered and reused. [source] Heterogeneous Palladium Catalysts for a New One-Pot Chemical Route in the Synthesis of Fragrances Based on the Heck ReactionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2007Maria Jose Climent Abstract The one-pot synthesis of the fragrance 4-(p -methoxyphenyl)butan-2-one, with raspberry scent, has been carried out using palladium on different supports such as magnesium oxide (MgO), hydrotalcite, hydroxyapatite (HA), aluminium oxide (,-Al2O3) and titanium dioxide (TiO2). The first pathway consists of a Heck coupling between 4-methoxyiodoanisole and methyl vinyl ketone followed by hydrogenation. Palladium supported on titanium dioxide showed the best performance for carrying out both consecutive steps giving 4-(p -methoxyphenyl)butan-2-one with high yields and selectivity. The Pd-TiO2 catalyst is more active than a homogeneous palladium complex that is well accepted in the literature as being highly active for performing Heck reactions. [source] Investigations on regio- and stereoselectivities in cycloadditions involving ,- (3-pyridyl)- N -phenylnitrone: Development of an efficient route to novel nicotine analogsJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2005Gurpinder Singh Thermal reactions of hitherto ,-(3-pyridyl)- N -phenylnitrone (1) with mono-substituted electron-rich and electron-neutral dipolarophiles are regio-, and stereo-selective (exo -selective), controlled by LUMO - dipole - HOMO- dipolarophile interaction, and furnish syn -5-substituted-3-(3-pyridyl)-isoxazolidines (5) in high yields. With electron deficient dipolarophiles such as acrylonitrile there is observed a loss of regioselectivity as well as stereoselectivity and the regioselectivity is reversed in reactions with methyl vinyl ketone and methyl acrylate, due to intervention of HOMO-dipole - LUMO-dipolarophile interaction, affording 4-substi-tuted-3-(3-pyridyl)-isoxazolidines (7) as major products. Reactions of nitrone (1) with disubstituted dipolarophiles such as methyl methacrylate and ethyl coronate furnish methyl syn -5-methy-3-pyridyl-1-phenyl-isoxazolidine-5-carboxylate (8) and ethyl anti -5-methy-3-pyridyl-1-phenyl-isoxazolidine-4-carboxylate (10), respectively, in high yields. Reaction with N -Phenylmaleimide affords novel isoxazolidino-pyrro-lidinediones bearing a 3-pyridyl moiety (11, 12). A mechanistic rationalization of the obtained results in terms of electronic, steric and secondary interactions is proffered. [source] Synthesis of dihydrothieno[2,3- b]pyridines based on titanium(IV) chloride-mediated michael reactions of 2-amino-4,5-dihydro-3-thiophenecarbonitriles with ,,,-unsaturated ketonesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2004Hiroshi Maruoka 2-Arnino-4,5-dihydro-3-thiophenecarbonitriles 1a-c reacted with ,,,-unsaturated ketones (e.g. methyl vinyl ketone 2 and benzalacetone 3) in the presence of titanium(IV) chloride to give the corresponding Michael adducts 4a-c and 5a-c. Thermal treatment of compounds 4a-c and 5a-c with titanium(IV) chloride caused intramolecular cyclocondensation to yield the corresponding tetrahydrothieno[2,3- b]pyridines 6a-c and 7a-c. Aromatization of 6a-c and 7a-c with potassium tert -butoxide in refluxing tert -butyl alcohol pro ceeded smoothly to afford the corresponding dihydrothieno[2,3- b]pyridines 8a-c and 9a-c. [source] Conformational analysis, Part 41.JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 6 2006-unsaturated carbonyl compounds, A modelling, LIS/NMR investigation of the conformations of Abstract A novel Lanthanide Induced Shift Analysis (LISA) is presented. In this analysis both the paramagnetic and the diamagnetic lanthanide induced chemical shifts are normalised separately in contrast to previous techniques in which only the paramagnetic shifts were normalised. This procedure is used together with molecular mechanics (MMFF94) and ab initio (RHF/6-31G, RHF/6-311G** and B3LYP/6-311G**) calculations to investigate s - cis/s - trans isomerism in some ,,, -unsaturated aldehydes, ketones and esters. In tiglic aldehyde 1 and trans -cinnamaldehyde 4 the s - trans conformer predominates with energy differences ,E (s - cis,s - trans) of 1.64 and 1.76,kcal/mol. In methyl vinyl ketone 2 and trans -cinnamyl methyl ketone 5 the populations of the s - cis and s - trans isomers are almost equal (,E 0.24 and 0.0,kcal/mol) and in methyl crotonate 3 and methyl trans -cinnamate 6 the s - cis conformer is more stable (,E ,0.72 and ,0.41,kcal/mol). These results are in agreement with both the MMFF94 and ab initio calculated energies for the compounds except tiglic aldehyde 1 in which all the calculated values are too large and cinnamyl ketone 5. In this compound the ab initio calculations predict the s - cis form to be more stable than the s - trans in contrast to both the MM calculations and the observed result which give both forms of equal energy. Also in both the MM and ab initio calculations phenyl substitution in the ketone (2 vs. 5) considerably stabilises the s - cis form. This is not observed in practise. In phenyl acetate 7 the B3LYP calculations give two equally stable structures, one planar one non-planar. The MMFF94 and MP2 calculations and the LIS analysis support the existence of only the non -planar conformer in solution, which is also the conformation of phenyl acetate in the crystal. Copyright © 2006 John Wiley & Sons, Ltd. [source] Synthesis of polar vinyl monomer,olefin copolymers by ,-diimine nickel catalystPOLYMER INTERNATIONAL, Issue 5 2001Maria M Marques Abstract Vinyl acetate, methyl methacrylate, acrylonitrile and methyl vinyl ketone were investigated for co- and terpolymerization with ethylene and ethylene,propylene. Precursor [bis(N,N,,-dimesitylimino)acenaphthene]dibromonickel, activated by methylaluminoxane was used as a catalyst system and trialkylaluminium was employed to block the polar groups for these polymerizations. Polymerization activities of the order of magnitude of 106 in the case of vinyl acetate and methyl methacrylate, and 105 in the case of acrylonitrile were achieved. Microanalysis and GPC of acrylonitrile copolymers found about 17 units of acrylonitrile per polymer chain. Copolymers with very different properties from the parent homopolymers were obtained in all cases except that of methyl vinyl ketone. © 2001 Society of Chemical Industry [source] Differentiation of isobaric compounds using chemical ionization reaction mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2005Kevin P. Wyche The technique of proton transfer reaction mass spectrometry (PTR-MS) couples a proton transfer reagent, usually H3O+, with a drift tube and mass spectrometer to determine concentrations of volatile organic compounds. Here we describe a first attempt to use chemical ionization (CI) reagents other than proton transfer species inside a PTR-MS instrument. The ability to switch to other types of CI reagents provides an extra dimension to the technique. This capability is demonstrated by focusing on the ability to distinguish several isobaric aldehydes and ketones, including the atmospherically important molecules methacrolein and methyl vinyl ketone. Two CI reagents were selected, H3O+ and NO+, both being cleanly generated in a low intensity radioactive source prior to injection into the drift tube. By recording spectra with both of these reagents, the contributions from different isobaric molecules can be separated by virtue of their unique spectrometric ,fingerprints'. The work demonstrates that this form of instrumentation is not restricted to proton transfer reagents and is the basis of a more general technique, chemical ionization reaction mass spectrometry (CIRMS). Copyright © 2005 John Wiley & Sons, Ltd. [source] Bifunctional Heterogeneous Catalysis of Silica,Alumina-Supported Tertiary Amines with Controlled Acid,Base Interactions for Efficient 1,4-Addition ReactionsCHEMISTRY - A EUROPEAN JOURNAL, Issue 41 2009Ken Motokura Dr. Abstract We report the first tunable bifunctional surface of silica,alumina-supported tertiary amines (SA,NEt2) active for catalytic 1,4-addition reactions of nitroalkanes and thiols to electron-deficient alkenes. The 1,4-addition reaction of nitroalkanes to electron-deficient alkenes is one of the most useful carbon,carbon bond-forming reactions and applicable toward a wide range of organic syntheses. The reaction between nitroethane and methyl vinyl ketone scarcely proceeded with either SA or homogeneous amines, and a mixture of SA and amines showed very low catalytic activity. In addition, undesirable side reactions occurred in the case of a strong base like sodium ethoxide employed as a catalytic reagent. Only the present SA-supported amine (SA,NEt2) catalyst enabled selective formation of a double-alkylated product without promotions of side reactions such as an intramolecular cyclization reaction. The heterogeneous SA,NEt2 catalyst was easily recovered from the reaction mixture by simple filtration and reusable with retention of its catalytic activity and selectivity. Furthermore, the SA,NEt2 catalyst system was applicable to the addition reaction of other nitroalkanes and thiols to various electron-deficient alkenes. The solid-state magic-angle spinning (MAS) NMR spectroscopic analyses, including variable-contact-time 13C cross-polarization (CP)/MAS NMR spectroscopy, revealed that acid,base interactions between surface acid sites and immobilized amines can be controlled by pretreatment of SA at different temperatures. The catalytic activities for these addition reactions were strongly affected by the surface acid,base interactions. [source] Ruthenium,Lewis Acid Catalyzed Asymmetric Diels,Alder Reactions between Dienes and ,,,-Unsaturated KetonesCHEMISTRY - A EUROPEAN JOURNAL, Issue 12 2007Jenny Rickerby Dr. Abstract The complex [Ru(Cp)(R,R -BIPHOP-F)(acetone)][SbF6], (R,R)- 1,a, was used as catalyst for asymmetric Diels,Alder reactions between dienes (cyclopentadiene, methylcyclopentadiene, isoprene, 2,3-dimethylbutadiene) and ,,,-unsaturated ketones (methyl vinyl ketone (MVK), ethyl vinyl ketone, divinyl ketone, ,-bromovinyl methyl ketone and ,-chlorovinyl methyl ketone). The cycloaddition products were obtained in yields of 50,90,% and with enantioselectivities up to 96,% ee. Ethyl vinyl ketone, divinyl ketone and the halogenated vinyl ketones worked best and their reactions with acyclic dienes consistently provided products with >90,% ee. ,-Chlorovinyl methyl ketone performed better than ,-bromovinyl methyl ketone. The reaction also provided a [4.3.1]bicyclic ring system in 95,% ee through an intramolecular cycloaddition reaction. Crystal structure determinations of [Ru(Cp)((S,S)-BIPHOP-F)(mvk)][SbF6], (S,S)- 1,b, and [Ru(Cp)((R,R)-Me4BIPHOP-F)(acrolein)][SbF6], (R,R)- 2,b, provided the basis for a rationalization of the asymmetric induction. [source] Boron (III) Tribromide or Titanium (IV) Bromide and Lewis Base Promoted Baylis-Hillman ReactionCHINESE JOURNAL OF CHEMISTRY, Issue 3 2002Min Shi Abstract It was found that, when the Baylis-Hillman reaction of arylaldehydes with methyl vinyl ketone was carried out at below -20 °C in the presence of boron (III) tribromide or titanium (IV) bromide using a catalytic amount of Lewis base such as amine, the brominated compounds and the Baylis-Hillman adducts could be obtained as the major products in good yields for various aryl aldehydes. But at room temperature, the elimination products were the major products. In addition, the palladium catalyzed allylic substitution reactions of the elimination products were also examined. [source] | ||||||||||||||||||||||||||||