- Nickel-catalyzed electrocarboxylation of allylic halides with CO2
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Nickel-catalyzed regioselective electrocarboxylation of allylic halides with CO2at atmospheric pressure has been developed by adjusting reaction parameters, including catalyst, solvent, temperature and additive. β,γ-Unsaturated carboxylic acids were obtained in moderate to good yields and with high chain selectivity. This reaction shows tolerance to functional groups. In addition, cyclic voltammetry was performed to provide the possible mechanism of nickel-catalyzed CO2allylation.
- Wu, La-Xia,Deng, Fang-Jie,Wu, Lin,Wang, Huan,Chen, Tai-Jie,Guan, Ye-Bin,Lu, Jia-Xing
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p. 13137 - 13141
(2021/08/03)
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- Efficient one-to-one coupling of easily available 1,3-dienes with carbon dioxide
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An efficient one-to-one coupling reaction of atmospheric pressure carbon dioxide with 1,3-dienes is realized for the first time through PSiP-pincer type palladium-catalyzed hydrocarboxylation. The reaction is applicable to various 1,3-dienes including easily available chemical feedstock such as 1,3-butadiene and isoprene. This protocol affords a highly useful method for the synthesis of β,γ-unsaturated carboxylic acid derivatives from CO2.
- Takaya, Jun,Sasano, Kota,Iwasawa, Nobuharu
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supporting information; experimental part
p. 1698 - 1701
(2011/05/04)
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- By using a palladium amidocarbonyl manufacturing method
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The present invention relates to a process for the preparation of beta- or gamma-unsaturated or saturated carboxylic acids. It relates more particularly to the hydroxycarbonylation of an organic compound comprising a conjugated unsaturation, such as butadiene, by the action of carbon monoxide and water in the presence of a palladium-based catalyst. The carboxylic acids thus obtained are preferably pentenoic acids. According to the invention, the reaction medium after the end of the hydroxycarbonylation stage is treated with hydrogen to reduce the palladium present in the 2+ oxidation state to palladium in the zero oxidation state and the precipitated palladium is recovered.
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- Method for preparing carboxylic acids by palladium carbonylation
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The present invention relates to a process for the preparation of β- or γ-unsaturated or saturated carboxylic acids. It relates more particularly to the hydroxycarbonylation of an organic compound comprising a conjugated unsaturation, such as butadiene, by the action of carbon monoxide and water in the presence of a palladium-based catalyst. The carboxylic acids thus obtained are preferably pentenoic acids. According to the invention, the reaction medium after the end of the hydroxycarbonylation stage is treated with hydrogen to reduce the palladium present in the 2+ oxidation state to palladium in the zero oxidation state and the precipitated palladium is recovered.
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- Conjugate addition of organolithium reagents to α,β-unsaturated carbocyclic acids
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Conjugate addition of primary, secondary, tertiary alkyi and phenyl lithium reagents to 2-alkenoic acids affords good yields of branched saturated carboxylic acids. Methyl groups at the α- and β-carbon of the 2-alkenoic acid decrease reactivity as acceptors, and foster deprotonation, respectively. The lithium enediolate resulting from the conjugate addition can react with electrophiles. PM3 calculations are in agreement with the substituent effects.
- Aurell, Maria Jose,Domingo, Luis Ramon,Mestres, Ramon,Munos, Elena,Zaragoza, Ramon Jose
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p. 815 - 830
(2007/10/03)
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- Process for the preparation of 3-pentenoic acid from butadiene using a nickel catalyst
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Process for making 3-pentenoic acid by reacting butadiene with carbon monoxide in the presence of nickel and an iodide source.
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- Alkylation of lithium dienediolates of butenoic acids. Regioselectivity effects of structure and leaving group of the alkylating agent
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Regioselectivity of alkylation of but-2-enoic acids I and 2 by alkyl halides strongly depends on the reactivity of the electrophile. High α selectivity results for saturated alkyl halides, whereas poor α-selectivity is obtained for highly reactive allyl and benzyl halides. For reactive alkylating halides selectivity is partly governed by the ion pairing aggregates of the dienediolates. Lithium bromide and the carboxylate generated in the ongoing reaction cause opposite effects on regioselectivity.
- Aurell, Maria J.,Gil, Salvador,Mestres, Ramon,Parra, Margarita,Parra, Lilian
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p. 4357 - 4366
(2007/10/03)
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- Lithium enediolates and dienediolates of carboxylic acids in synthesis: Alkylation with secondary halides
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High yields in the alkylation of dianions of α,β-unsaturated carboxylic acids with secondary halides can be obtained despite elimination reactions occurring. α-Regioselectivity for the alkylation of but-2-enoic acids (1-4) is seldom obtained. Although dou
- Brun, Eva M.,Gil, Salvador,Mestres, Ramon,Parra, Margarita
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p. 15305 - 15320
(2007/10/03)
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- Regioselective Synthesis of β,γ-Unsaturated Acids by the Electrochemical Carboxylation of Allylic Bromides Using a Reactive-metal Anode
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Electrolysis of γ-mono and disubstituted allylic bromides in the presence of atmospheric pressure of carbon dioxide using a platinum cathode and a magnesium anode gave regioselectively the corresponding γ-mono and disubstituted β,γ-unsaturated carboxylic acids in 34-71percent yields.
- Tokuda, Masao,Kabuki, Takashi,Katoh, Yoshitaka,Suginome, Hiroshi
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p. 3345 - 3348
(2007/10/02)
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- Carbanions. 23. Cleavage of 1,2-Diphenylethane and Derivatives by Cs-K-Na Alloy. Cometitive Rates of Bond Scission
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The following hydrocarbons are cleaved at a C-C bond to allylic and or/benzylic cesium compounds within 2 h by Cs-K-Na alloy in THF at -75 deg C: meso-2,3-diphenylbutane, 2,3-dimethyl-2,3-diphenylbutane, 1,2,2-triphenylpropane, 4-phenyl-1-butene, bibenzyl, and eight o-,m-, or p-methyl derivatives of bibenzyl.Under the same conditions 2-methyl- and 3-methyl-4-phenyl-1-butene were partially cleaved, 4,4'-dimethylbibenzyl was only slightly cleaved, and 9,10-dihydrophenanthrene was not detectably cleaved, while 10,11-dihydro-5H-dibenzocycloheptene underwent alternative C-H bond cleavage.Under the present reaction conditions 4,4'-dimethylbibenzyl and 9,10-dihydrophenanthrene were converted largely to dianions.It is suggested that all of the compounds undergoing cleavage are converted to dianions prior to cleavage.From competitive experiments the rates of reductive cleavage of most of these hydrocarbons relative to bibenzyl have been measured at -75 deg C.The relative rates of cleavage of m- and p-methylderivatives of bibenzyl may be correlated with the relative equilibrium acidities of toluene, m-xylene, and p-xylene in a modified Hammett relationship.Cleavages of benzylic C-C bonds are believed to occur by way of a preferred transition-state geometry,7, which permits the ?* orbital of the bond undergoing cleavage to interact with the HOMO's of both aromatic rings.Compounds that cannot attain this transition-state geometry are cleaved slowly if at all.The variable effect upon reaction rate of methyl groups near the bond undergoing cleavage are discussed in terms of ground-state and transition-state atrain, solvation, and polarizability of methyl groups.According to labeling experiments (o-methylbenzyl)cesium undergoes ready intramolecular sigmatropic migration of hydrogen from the methyl group to the methylene group when warmed from -75 deg C to near room temperature.
- Grovenstein, Erling,Bhatti, Amjad M.,Quest, Dean E.,Sengupta, Dibyendu,VanDerveer, Don
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p. 6290 - 6299
(2007/10/02)
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