Arenes Methyl acrylate

The vinyl triflate of Komfeld s ketone has been subjected to Heck reactions with methyl acrylate, methyl methacrylate, and methyl 3-(Af-rerf-butoxycarbonyl-lV-methyl)amino-2-methylenepropionate leading to a formal synthesis of lysergic acid [259]. A similar Heck reaction between l-(phenylsulfonyl)indol-5-yl triflate and dehydroalanine methyl ester was described by this research group [260]. Chloropyrazines undergo Heck couplings with both indole and 1-tosylindole, and these reactions are discussed in the pyrazine Chapter [261], Rajeswaran and Srinivasan described an interesting arylation of bromomethyl indole 229 with arenes [262]. Subsequent desulfurization and hydrolysis furnishes 2-arylmethylindoles 230. Bis-indole 231 was also prepared in this study. 

Planar chiral arene Cr(CO)3 complexes have been shown to undergo highly diastereoselective cycloadditions and Kiindig has extended this protocol to the [3+2] cycloadditions of azomethine ylides (96). Enantiopure ortho- substituted p -benzaldehyde complex 337 underwent condensation with an ot-amino ester to afford imine 338 in the presence of EtaN. Subsequent treatment with methyl acrylate at ambient temperamre in the presence of LiBr and EtaN delivered cycloadduct 339, with excellent stereoinduction and high material yield. Photoinduced oxidative decomplexation in air furnished the final arylpyrrolidines (Scheme 3.114). 

The possibility of the intermediacy of the triplet state of benzene itself has been discussed by Atkins et al. [108], Photoaddition of alkenes to arenes is often accompanied by the formation of dimers of the alkene, a reaction sensitized by triplet benzene. With methyl acrylate and methyl vinyl ketone, however, it was found that the ratio of ortho cycloadducts to alkene dimers increased with the concentration of benzene. Because the yield of T, benzene increases with benzene concentration, these results might indicate that ortho photocycloaddition of aery-... 

Complexes 53 are efficient catalysts for the homodimerization of 1-octene and styrene. Complex 53a bearing the sterically more demanding l,3-bis(2,6-diisopropylphenyl)-NHC ligand shows a higher reactivity than the mesityl-substituted 53b. These complexes also catalyze the CM of 1-octene or styrene with methyl acrylate ( 80% yield), the RCM of diethyl diallylmalonate at 40 °C ( 95% yield), and the ROMP of cyclooctene at 60 °C ( 90% yield). By GC-MS analysis the presence of free p-cymene was detected in the beginning of the reactions. From these results it may be concluded that the first step of the catalytic cycle is arene decoordination to generate a 12-electron [OsCl(= CHPh)(NHC)] + derivative as the catalytically active species [102],... 

The X-ray structure of the indicated borane-methyl acrylate complex (Fig. 19) unequivocally confirms the design concept. The solid state structure shows a close contact (3.40 A from the center of the substituted phenyl ring to the carbonyl carbon) between the electron-rich arene and boron-bound methoxycarbo-nyl group, an arrangement which also exists in solution. As the polarizability of the aryl group is increased, the dienophile is drawn closer to the arene, suggestive of a dipole-induced attractive interaction. The air-sensitive catalyst 13 was synthesized by way of a resolution in 5 steps. 

A triflyloxy substituent may replace the iodo substituent in an efficient approach to carbon-carbon bond formation in alkenes and arenes. Applied to pyrimidine chemistry, it has been found that cross-coupling of 5-triilyloxyuracil with alkenes and alkynes leads to 5-alkenylated and 5-alkynylated uracils (87H355). Similarly M-methyl- or Af,N -dimethyl-pyrimidin-5-yl triflate (16) reacts with styrene, acetonitrile, methyl acrylate, or methyl vinyl ketone to form the alkenylated products (17) (87H355). 

The arene substrates are not limited to simple benzene derivatives. A variety of het-eroarenes can also participate in alkene arylations to generate the desired coupling products. Stoichiometric oxidative coupling of aromatic heterocycles such as furan, thiophene, selenophene, A-methylpyrrole, benzofiiran and benzothiophene with a variety of alkenes, including acrylonitrile, styrene and methyl acrylate, have been extensively studied by Fu-jiwara and coworkers [8]. Furan, thiophene, selenophene and A-methylpyrrole are easily alkenylated with alkenes to give 2-alkenylated and 2,5-dialkenylated heterocycles in relatively low yields (3 6%) [8a], while the reactions of benzofuran and benzothiophene with alkenes produced a mixture of 2- and 3-alkenylated products [8b]. 

The reaction, as further extended to acrylate esters such as methyl-acrylate and butyl-acrylate, displayed 79 and 18% yield in the reaction with f-butyl diazoacetate catalyzed by the resorcin[4]arene capsule, while with the occupied cavity yields were both lower than 5% and in the absence of the capsule decomposition products were detected (Fig. 7.12). 

With Ruthenium In 2001, Milstein s group [74] reported the first nondirected oxidative arylation of olefins using Ru catalysts. In this approach, a series of arenes (in excess), which included chlorobenzene, toluene, anisole, and />-xylene, were treated with RUCI3-3H2O (0.4mol% ) and either methyl acrylate, ethene, or CH2=CH(CF2)3CF3 in the presence of both CO and oxygen and heated in a sealed vessel to 180 °C for 48 h. The yields were only moderate, and turnover numbers (TONs) of 5.4—118 could be obtained. The active catalyst was considered to be an electrophilic Ru carbonyl species. 

A year later, Milstein and co-workers described a ruthenium-catalyzed oxidative coupling of arenes with olefins. The reaction in which O2 can be directly used as the oxidant required CO pressure (6.1 atm.) and proceeded with good activities (up to TON = 88). Both, electron-donating substituents on the arene, and electron-deficient alkenes methyl acrylate) appeared to be the most efficient coupling partners. Low activities were obtained for... 

Phenoxypropanoic acid, 3-(phenylthio)propanoic acid, 4-phenylbutanoic acid and the corresponding ethyl and methyl esters have been pyrolysed between 520 and 682 K.10 Analysis of the pyrolysates showed the elimination products to be acrylic acid and the corresponding arene. The thermal gas-phase elimination kinetics and product analysis have been found compatible with a thermal retro-Michael reaction pathway involving a four-membered cyclic transition state. 

Iron-arene complexes are known to exhibit extremely high photoactivity as initiators. Quantum efficiencies have been found to be greater than I in the photopolymerisation of dicyanate esters. Phenylglycine derivatives have been found to be excellent co-synergists for the iron-arene complexes when used in conjunction with dyes and amines. Complexes of various types have also been proposed. Maleic anhydride-THF complexes have been used for the photopolymerisation of oligourethane acrylates while metal-ion complexes of spiropyran copolymers undergo reversible polymer precipitation. Azo and polyazo initiators have been used to make butadiene-isoprene block copolymers while charge-transfer complexes of morpholine-chlorine induce the radical polymerisation of methyl methacrylate. The presence of zinc chloride enhances the... 

One of the simplest examples is the alkylation of aromatics. As mentioned above, Periana reported an Ir(lll)(acac)3 complex that could activate benzene and catalyze anti-Markovnikov additions of olefins to the aryl C-H bond. In this reaction, a 61 39 ratio of linear branched isomers was observed (Equation (25)). An iridium-phenyl complex was shown to be an intermediate. Gem-disubstituted and acrylate olefins proved to be minimally reactive. More recently, a bis-tropolonato iridium(in) methyl complex was found to catalyze the anti-Markovnikov addition of olefins to arenes with slightly lower activity, but similar selectivity. ... 

Arens, M., R. Spilker, Fatty acid amidopropylbetaines—determination of fatty acid amidopro-pylamine—collaboration of the DGF. Communication 150 German standard methods for study of fats, fatty products, surfactants and related materials. Communication 116 Analysis of surface active materials XXV (in German), Fett Wiss. TechnoL, 1995, 97,468-470. Schwarz, G., P. Leenders, U. Ploog, Condensation products of fatty acids or their methyl esters with aminoethylethanolamine (in German), Fette, Seifen, Anstrichm., 1979,81, 154-158. Takano, S., K. Tsuji, Structural analysis of the amphoteric surfactants obtained by the reaction of l-(2-hydroxyethyl)-2-alkyl-2-imidazoline with ethyl acrylate,/. Am. Oil Chem. Soc., 1983, 60,1798-1806. 

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