Reaction Of Methyl Vinyl Ketone Research Articles

Synthesis of Rigid Macrocyclic Phenols and Their Catalytic Applications in Diels‐Alder Reactions

AbstractMacrocyclic catalysts having a phenol‐acetylene‐phenol triad were developed as a hydrogen‐bond donor catalyst. The rigid macrocyclic framework suppressed intramolecular hydrogen bonds between neighboring phenolic hydroxy groups. The preorganized phenol‐acetylene‐phenol moiety formed efficient intermolecular hydrogen bonds with carbonyl groups of substrates. The hydrogen‐bond donor catalysts accelerated the Diels‐Alder reaction of methyl vinyl ketone with cyclopentadiene. The catalytic ability was higher than that of an acyclic counterpart.

Highly Efficient Asymmetric Morita–Baylis–Hillman Reaction Promoted by Chiral Aziridine-Phosphines

Continuing our research on the use of organophosphorus derivatives of aziridines in asymmetric synthesis and expanding the scope of their applicability, chiral aziridine-phosphines obtained earlier in our laboratory were used as chiral catalysts in the asymmetric Morita–Baylis–Hillman reaction of methyl vinyl ketone and methyl acrylate with various aromatic aldehydes. The desired chiral products were formed in moderate to high chemical yields and with enantiomeric excess reaching value of 98% ee in some cases. The use of catalysts being pairs of enantiomers led to the desired products with opposite absolute configurations.

Insight into the formation of organosulfur compounds from the reaction of methyl vinyl ketone with sulfite radical in atmospheric aqueous phase

The formation of organosulfur compounds through the reaction of organic species with sulfoxy radicals produced from the metal-catalyzed oxidation of S(IV) has become of recent concern, but the detailed formation mechanism still remains unanswered. In this work, we studied the mechanism of the initial reaction of methyl vinyl ketone (MVK) by SO3− radical and the subsequent sulfonate formation processes using DFT calculation. The results show that dissolved O2 addition to the initial product is more favorable than the addition of MVK to the initial product due to its lower activation free energy (6.19 kcal mol−1). The produced peroxyl radical can undergo bimolecular self-reactions, unimolecular decay and bimolecular reaction with other species (HSO3− and H2O) to form alcohols and ketones. Among them, two pathways are most likely to occur: one belongs to bimolecular self-reactions, whose activation free energy is 16.20 kcal mol−1; the other is derived from bimolecular reaction of peroxyl radical with HSO3−, which needs to overcome the activation free energy of 18.47 kcal mol−1. This work displays a complete description of the formation process of sulfonates and thus can provide some insights into the further study on the formation of organosulfur compounds.

Direct formylation of 2-pyridone core of 3-N-methylcytisine via Duff reaction; synthesis of 9-enyl, 9-ynyl and 9-imino derivatives

The first direct synthesis of 3-N-methyl-9-formylcytisine via electrophylic formylation is described. It is established, that Vilsmeier-Haack and Gatterman variants of this reaction are unsuccessful in the case with 3-substituted (-)-cytisine derivatives, but Duff procedure (with hexamethylenetetramine in trifluoroacetic acid) gives a possibility to obtain the target pseudo aromatic aldehyde with the 69% yield. Convenient precursors for [4 + 2]- or [3 + 2]-cycloaddition reactions are obtained by means of condensation of synthesized 3-N-methyl-9-formylcytisine with acetone, nitromethane and phosphorous ylides with yields from 70 to 87%. Alternative aprroach to alkenyl products and to 9-alkynyl-3-methylcytisine is realized using the Heck and Sonogashira cross-coupling reactions of methyl vinyl ketone, cyclohexenone or trimethylsilylacetylene with 9-bromo-3-methylcytisine (55, 70 and 60% accordingly). It is shown, that interaction of 3-N-methyl-9-formylcytisine with hydroxylamines leads to corresponding nitrone (93%) and oxime (70%). All individual compounds are isolated by column chromatography and completely characterized on the basis of NMR spectroscopy data.

Proline-Mediated Baylis–Hillman Reaction of Methyl Vinyl Ketone without a Co-catalyst under Solvent-Free Conditions

A proline-mediated Baylis–Hillman reaction of methyl vinyl ketone with aromatic aldehydes has been carried out without using any co-catalyst, under solvent-free conditions. The reaction works efficiently at 60 °C in the presence of a small amount of water to afford the Baylis–Hillman adducts in reasonable to very good yields over 8–48 h. The absence of a co-catalyst suggests that proline plays a role in the proton-transfer step of the reaction mechanism, in addition to its proposed involvement in the iminium ion formation and conjugate addition. This would, in principle, imply that proline acts as a trifunctional catalyst in the reaction, and mechanistic studies to gain a deeper understanding of this aspect should provide further insights in the future.

Multivalency as a key factor for high activity of selective supported organocatalysts for the Baylis-Hillman reaction.

The polystyrene-supported N-alkylimidazole-based dendritic catalysts for the Baylis-Hillman reaction exhibit one of the strongest beneficial effects of multivalent architecture ever reported for an organocatalyst. The yields in the model reaction of methyl vinyl ketone with p-nitrobenzaldehyde are more than tripled when a non-dendritic catalyst is replaced by a second- or third-generation analogue. Moreover, the reaction of the less active substrates will not occur with the non-dendritic catalyst and will proceed to a significant extent only with the analogous catalysts of higher generations. A substantial additional enhancement of the reaction yield could be achieved by increasing the content of water in the reaction solvent. The plausible cause of the dendritic effect is the assistance of the second, nearby imidazole moiety in the presumably rate-determining proton transfer in the intermediate adduct, after the first imidazole unit induced the formation of the new carbon-carbon bond.

Addition of diphenylacetylene and methylvinylketone to aluminum complex of redox-active diimine ligand

Diphenylacetylene reacts with aluminum complex (dpp-bian)AlEt(Et2O) (1) (dpp-bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) in the absence of any solvent at 110–130 °C under vacuum to give compound [dpp-bian(PhCCPh)]AlEt (2). The reaction of methylvinylketone with complex 1 easily proceeds at ambient temperature in Et2O and results in the formation of compound [dpp-bian(CH2–CHC(Me)–O)]AlEt (3). Both reactions proceed via addition of unsaturated organic substrate across Al–N–C bond sequence in complex 1. Complexes 2 and 3 have been characterized by IR and 1H NMR spectroscopy. Molecular structures of 2 and 3 have been determined by single-crystal X-ray analysis. Complex 2 was found to be catalyst for the reaction between phenylacetylene and diphenylamine. A full conversion of the reagents was achieved with 5 mol% of complex 2 in benzene in 140 h at 110 °C resulting N-phenyl-2-(1-phenylvinyl)aniline (4a) as the major product (87%).

Oligomeric products and formation mechanisms from acid-catalyzed reactions of methyl vinyl ketone on acidic sulfate particles

Methyl vinyl ketone (MVK) is a key first-generation product from atmospheric isoprene photo-oxidation, especially under high-NOx conditions. In this work, acid-catalyzed reactions of gas-phase MVK with ammonium sulfate (AS), ammonium bisulfate (ABS), and sulfuric acid (SA) particles were investigated in a flow reaction system at relative humidity (RH) of 40 % and 80 %. Ultra-performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry (UPLC/ESI-TOFMS) and gas chromatography-mass spectrometry (GC-MS) are utilized to identify particle-phase products for developing the reaction mechanisms. High-order oligomers such as dimers and tetramers were detected when ABS and SA particles were used, while no oligomeric products were found when AS particles were used. Particle-phase oligomeric products were formed via i) acid-catalyzed aldol reaction with or without dehydration and/or ii) acid-catalyzed hydration followed by oligomerization. Reactions on SA particles yield more abundant and higher-order oligomers up to hexamers than on ABS particles. Moreover, aldol reaction occurred only on SA particles, but hydration followed by oligomerization occurred in both ABS and SA particles. The high RH condition with the same type of acidic particles was found to favor hydration and facilitate the subsequent oligomerization, while the low RH condition with the same type of acidic particles was found to favor aldol reaction with dehydration (aldol condensation). Overall, the findings suggest acidic particles can facilitate the formation of high-order oligomers in the particle phase, with particle acidity and RH as key factors.

Addition of bisulfite ions to methyl vinyl ketone and methacrolein relevant to atmospheric processes

Methacrolein and methyl vinyl ketone are highly reactive carbonyls that play a pivotal role in the formation of secondary organic aerosols in the Earth’s atmosphere. Both carbonyls are the major products of isoprene oxidation. We show that among the atmospheric sinks of methacrolein and methyl vinyl ketone, the aqueous-phase addition of bisulfite anions to their molecules can be relevant under polluted conditions with the increased presence of sulfur dioxide. We demonstrate that aqueous-phase reactions of methyl vinyl ketone and methacrolein with bisulfite anions lead to the formation of primary and secondary organic hydroxysulfonates which currently are not included in the atmospheric chemistry modelling, but can be relevant in mechanisms explaining the formation and growth of the secondary organic aerosols from atmospheric carbonyls. The rate constants for all aqueous-phase reactions involved were determined. The primary addition of bisulfite anions to methacrolein was found significantly faster than that to methyl vinyl ketone, with rate constants kMAC1f = 8 and kMVK1f = 0.18 mol –1 dm s at room temperatures, respectively. The rate constant for the bisulfite addition to methacrolein was ten times faster than reported in the literature. The kinetic and mass spectrometric analyses revealed that in both cases, the dominating product was the C4 alpha-hydroxysulfonate (a primary adduct), while the C4 alpha-hydroxy disulfonate (a secondary adduct or diadduct) was produced only in trace quantities. The primary addition of bisufite anions to methacrolein and methyl vinyl ketone should be considered in atmospheric studies relevant to areas with enhanced presence of sulfur dioxide providing sufficiently high concentrations of bisulfite ions in atmospheric waters.

Rapid Quantification of the Activating Effects of Hydrogen-Bonding Catalysts with a Colorimetric Sensor

A sensor has been developed to quickly and simply assess the relative reactivity of different hydrogen-bonding catalysts. Specifically, blue-shifts seen upon treatment of H-bonding catalysts with the colorimetric compound 7-methyl-2-phenylimidazo[1,2-a]pyrazin-3(7H)-one correlate well to the K(eq) of binding to the sensor. The blue-shifts also show a high degree of correlation with relative rates in Diels-Alder reactions of methyl vinyl ketone and cyclopentadiene employing the H-bonding catalysts. The relevance of the sensor blue-shifts to the LUMO-lowering abilities of the H-bonding catalysts is discussed.

Chiral 3-aminopyrrolidines as a rigid diamino scaffold for organocatalysis and organometallic chemistry

Over 20 new and easily prepared diamines were screened for the asymmetric Morita–Baylis–Hillman reaction. Chiral non-racemic 3-( N, N-dimethylamino)-1-methylpyrrolidine was found to promote efficiently the reaction of methyl vinyl ketone and substituted benzaldehydes. Enantiomeric excesses up to 73% were reached with electron-deficient benzaldehyde derivatives. After a simple deprotonation, one of these diamines was transformed into a chiral mixed aggregate for the enantioselective synthesis of ( R)-1- o-tolylethanol with 76% ee.

N-Alkylimidazole-Decorated Dendritic Catalysts for Baylis-Hillman Reaction

Polymer-supported dendritic ­catalysts [Gn(E-Im), Gn(A-Im), Gn(T-Im)] were ­prepared from Wang resins and N-alkylated imidazoles (1-3), and applied to the Baylis-Hillman reaction. Thus, the Baylis-Hillman reaction of methyl vinyl ketone and 4-nitrobenzaldehyde was performed with the catalytic resin G2(A-Im) (0.1 mmol of N-alkylated imidazole units) in DMF-H2O (9:1, v/v) at room temperature for 4 h to afford ­adduct 4 in 91% yield.

X-Ray absorption in homogeneous catalysis research: the iron-catalyzed Michael addition reaction by XAS, RIXS and multi-dimensional spectroscopy

A survey over X-ray absorption methods in homogeneous catalysis research is given with the example of the iron-catalyzed Michael addition reaction. A thorough investigation of the catalytic cycle was possible by combination of conventional X-ray absorption spectroscopy (XAS), resonant inelastic X-ray scattering (RIXS) and multi-dimensional spectroscopy. The catalytically active compound formed in the first step of the Michael reaction of methyl vinyl ketone with 2-oxocyclopentanecarboxylate (1) could be elucidated in situ by RIXS spectroscopy, and the reduced catalytic activity of FeCl(3) x 6 H(2)O (2) compared to Fe(ClO(4))(3) x 9 H(2)O (3) could be further explained by the formation of a [Fe(III)Cl(4)(-)](3)[Fe(III)(1-H)(2)(H(2)O)(2)(+)][H(+)](2) complex. Chloride was identified as catalyst poison with a combined XAS-UV/vis study, which revealed that Cl(-) binds quantitatively to the available iron centers that are deactivated by formation of [FeCl(4)(-)]. Operando studies in the course of the reaction of methyl vinyl ketone with 1 by combined XAS-Raman spectroscopy allowed the exclusion of changes in the oxidation state and the octahedral geometry at the iron site; a reaction order of two with respect to methyl vinyl ketone and a rate constant of k = 1.413 min(-2) were determined by analysis of the C=C and C=O vibration band. Finally, a dedicated experimental set-up for three-dimensional spectroscopic studies (XAS, UV/vis and Raman) of homogeneous catalytic reactions under laboratory conditions, which emerged from the discussed investigations, is presented.

Phospha‐michael reactions involving p‐heterocyclic nucleophiles

AbstractP‐heterocyclic γ‐ketophosphonates were synthesized by the Michael reaction of methyl vinyl ketone with dibenzo‐1,2‐oxaphosphorine 2‐oxide, 1,3,2‐dioxaphosphorine 2‐oxide and benzo‐1,3,2‐dioxaphospholane 2‐oxide, respectively. In the first two cases, 50% of 1,8‐diazabicyclo[5.4.0[undec‐7‐ene had to be used that was also required in the addition of dibenzooxaphosphorine oxide to cyclohexenone to result in the formation of the corresponding γ‐ketophosphonate. The addition of dibenzooxaphosphorine oxide to less reactive 1,2‐dihydrophosphinine oxide was accomplished after activation by an equimolar amount of trimethylaluminum to afford a 3‐P(O)<‐1,2,3,6‐tetrahydrophosphinine oxide, which was subjected to catalytic hydrogenation to provide the corresponding 1,2,3,4,5,6‐hexahydrophosphinine oxide. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:288–292, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20421

Zn-Catalyzed Aldol Reaction of Methyl Vinyl Ketone

Zn-Catalyzed Aldol Reaction of Methyl Vinyl Ketone

Direct Asymmetric Zn—Aldol Reaction of Methyl Vinyl Ketone and Its Synthetic Applications.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Direct Asymmetric Zn−Aldol Reaction of Methyl Vinyl Ketone and Its Synthetic Applications

A direct catalytic asymmetric aldol reaction of methyl vinyl ketone is described using our dinuclear zinc catalyst. The obtained aldol adduct functions as a bifunctional building block by utilization of the vinyl functionality. For example, convergent fragment coupling methods have been demonstrated via highly diastereoselective cycloaddition of nitrile oxide after reduction into 1,3-diol or via cross-metathesis reaction.

Mechanism of Scandium Ion Catalyzed Diels−Alder Reaction of Anthracenes with Methyl Vinyl Ketone

Rates of Diels-Alder cycloadditions of anthracenes with methyl vinyl ketone (MVK) are accelerated significantly by the presence of scandium triflate [Sc(OTf)3]. Sc(OTf)3 also promotes photoinduced electron-transfer reactions from various electron donors to MVK significantly. Comparison of the promoting effect of Sc(OTf)3 in photoinduced electron-transfer reactions of MVK with the catalytic effect of Sc(OTf)3 in the Diels-Alder reaction of 9,10-dimethylanthracene with MVK has revealed that the MVK-Sc(OTf)3 complex is a reactive intermediate in both the Diels-Alder and photoinduced electron-transfer reactions. The observed second-order rate constants of the Sc(OTf)3-catalyzed Diels-Alder reactions of anthracenes with MVK are by far larger than those expected from the observed linear Gibbs energy relation for the Diels-Alder reactions of anthracenes with stronger electron acceptors than MVK, which are known to proceed via electron transfer. This indicates that the Sc(OTf)3-catalyzed Diels-Alder reactions of anthracenes with MVK does not proceed via an electron-transfer process from anthracences to the MVK-Sc(OTf)3 complex.

Canonical Sampling Method for Initial Conditions for Reactive Flux Calculations Using Nose-Hoover Chains

Canonical sampling method has been presented to generate the initial conditions for reactive flux studies of organic reactions in water. Velocity Verlet version of Nose-Hoover chain dynamics algorithm has been employed to sample the initial conditions according to canonical distribution. The unstable normal mode of a transition state has been introduced to define a dividing plane separating reactant and product regions in reaction processes. This method has been implemented and tested for the case iels-Alder reaction of methyl vinyl ketone (MVK) and cyclopentadiene (CPD) in water, providing a reliable tool for further reactive flux molecular dynamics studies in condensed media.

Methanofullerene-Based Palladium Bis(amino)aryl Complexes and Application in Lewis Acid Catalysis

Synthetic routes have been developed for the attachment of palladium(II) bis(amino)aryl (NCN or C6H2{CH2NMe2}2-2,6)- complexes to C60. Using diazo and Bingel addition reactions, various methanofullerene NCN-SiMe3 compounds (C60-L-NCN-SiMe3, L = C(Me), C(CO2Et)CO2CH2, and C(Me)C6H4CC) have been prepared and characterized. Electrophilic palladation of these ligands was achieved with Pd(OAc)2, leading to the corresponding C60-L-NCN·PdCl complexes. These were converted into active Lewis acid catalysts for the aldol condensation and the Michael reaction. Catalytic tests show that the activity of cationic methanofullerene NCN-palladium complexes in the aldol reaction between benzaldehyde and methyl isocyanoacetate is comparable to the parent unsupported NCN palladium complex. However, in the Michael reaction of methyl vinyl ketone and ethyl cyanoacetate, the fullerene catalysts are not only significantly slower but also undergo a deactivation/decomposition process during the reaction. Preliminary retention measurements using a nanofiltration membrane have shown 72% retention of the palladium complex C60-C(Me)-(NCN)PdCl.