- Lithium naphthalenide-induced reductive alkylation and addition of aryl-and heteroaryl-substituted dialkylacetonitriles
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Lithium naphthalenide (LN)-induced reductive alkylation/addition reactions of aryl-, pyridyl-, and 2-thienyl-substituted dialkylacetonitriles have been investigated. Upon treatment with LN in THF at -40°C, both aryl and pyridyl precursors could undergo the reductive decyanation smoothly, and the in situ generated carbanions could be readily trapped by alkyl halides, ketones, aldehydes, or even oxygen to afford a wide range of functionalized aromatic derivatives bearing a newly established quaternary carbon. To effect the desired reductive alkylation of 2-thienyldialkylacetonitriles, a much lower temperature such as -100°C was required. Also with these substrates, an interesting ring-opening/S-alkylation process was observed when the reductive alkylation were performed at -78°C to give 1-alkylsulfanyl-1,3,4-trienes. A mechanistic discussion is given for this observation.
- Tsao, Jing-Po,Tsai, Ting-Yueh,Chen, I-Chia,Liu, Hsing-Jang,Zhu, Jia-Liang,Tsao, Sheng-Wei
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experimental part
p. 4242 - 4250
(2011/02/25)
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- An electron-deficient diene as ligand for palladium-catalyzed cross-coupling reactions: An efficient alkylation of aryl iodides by primary and secondary alkylzinc reagents
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An electron-deficient diene, L1, was found to be an effective ligand in facilitating palladium-catalyzed Negishi couplings involving primary and secondary alkylzinc reagents. The reactions took place readily at 60 °C in THF with 5 mol% of a catalyst generated in situ from bis(acetonitrile) palladium dichloride [PdCl2(MeCN)2] and L1, and functional groups such as chloro, bromo, etc. attached to phenyl ring as well as β-H atoms adjacent to the reaction site were well tolerated. The problematic isomerizations in secondary alkyzinc reagents involved in the reactions reported in the literature were also observed in our system when isopropylzinc chloride was employed alone as the nucleophile. However, the isomerization was significantly suppressed when i-Pr2Zn was utilized in the presence of L1.
- Liu, Qiang,Duan, Hui,Luo, Xiancai,Tang, Yang,Li, Gang,Huang, Rong,Lei, Aiwen
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supporting information; experimental part
p. 1349 - 1354
(2009/05/30)
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- Decarbonylative diarylation reaction of N-tosylated α-amino acids
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The reaction of various N-tosylated α-amino acids with arenes in the presence of sulfuric acid afforded the corresponding diarylated derivatives in moderate yields, which were generated via decarbonylative arylation followed by Friedel-Crafts reaction of the generated tosylamide derivatives.
- Seong, Mi Ra,Lee, Hong Jung,Kim, Jae Nyoung
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p. 6219 - 6222
(2007/10/03)
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- Modern Friedel-Crafts Chemistry. Part 24. Alkylation of Benzene with 1,2-Dibromo-3-chloro-2-methylpropane in the Presence of Lewis and Bronsted Acid Catalysts
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The major alkylation products of benzene with 1,2-dibromo-3-chloro-2-methylpropane are 1-X-2-methyl-3,3-diphenylpropane (X = Cl, Br) with AlCl3 and 1,4-bis-(1-bromo-3-chloro-2-methylpropyl)benzene with AlCl3-CH3NO2 or K10 montmorillonite (K10 Clay); minor products include di- and tri-phenylated butanes and/or 2-methyl-1-phenylindane.
- Albar, Hassan A.,Khalaf, Ali A.,Bahaffi, Saleh O.
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- Catalytic activity of K10-montmorillonite in reaction of arenes with some mono- and di-functional alkylating agents, mostly derived from isobutane and isobutene
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K10-montmorillonite has been tested as Friedel-Crafts catalyst in the alkylation of benzene, toluene and anisole with one or more of the alkylating agents 1-10. The reaction products consisted essentially of 1,1- and 1,2-diaryl-2-methylpropane derivatives (e.g. 11 and 12 respectively) together with side products resulting from transalkylation, monoalkylation, hvdride transfer and elimination. K 10-montmorillonite has also been used to catalyse the alkylation of naphthalene with benzyl alcohol whereby a mixture of α-and β-benzylnaphthalene is obtained. The results, explained in terms of carbocation transformations, show K 10-montmorillonite to be a mild catalyst with no subsequent side-chain isomerising ability just like FeCl3, AlCl3-CH3NO2, TiCl4 and ZrCl4.
- Albar,Basaif,Khalaf, Ali A.
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p. 161 - 166
(2007/10/03)
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- Modern Friedel-Crafts chemistry. XVIII. Alkylation of benzene with 1,2-dibromo-2-methylpropane, 1-chloro-2-methyl-2-phenylpropane, 3-chloro-2-methyl-1-propene and 1-bromo-2-methyl-1-propene
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Alkylation of benzene with the title compounds gave similar product mixture containing isomeric 1,2-diphenyl-2-methylpropane (9), 1,1-diphenyl-2-methylpropane (10) and dl and meso-2,3-diphenylbutane (11) in alkylations catalysed by appreciable amounts of AlCl3 or Al-HCl(g) and of 9 and 10 only in alkylations catalysed by the milder catalysts AlCl3-CH3NO2, ZrCl4 and TiCl4.In almost all cases, 9 and 10 were always produced in an apparent equilibrium ratio of approximately 2 : 1.These new results disproved numerous earlier reports claiming the products from these reactions to contain only 9 and meso-11 depending on catalyst and conditions.Mechanistic interpretations are given to account for the results.
- Khalaf, Ali Ali,Albar, Hassan A.
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- Substituent Effects in the Decomposition of t-Alkyl t-Butyl Peroxides
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The decomposition rates and products of various t-alkyl t-butyl peroxides were examined in cumene at several temperatures.The decomposition of these peroxides took place homolytically, depending on the structure of the t-alkoxyl moieties (RC(CH3)2-O), and was retarded in the order: R = (CH3)3CCH2 > (CH3)2CH > CH3CH2CH2 > PhCH2 > CH3CH2 > ClCH2 > CH3.The rate constants for the electron-donating alkyl substituents at 150 deg C are correlated very well to a Taft equation (log kd = -10.93Σ?*-6.61 (correlation coefficient of 0.9501)), which is fairly different from the equation log kd = -0.131Σ?*-3.422 for electron-withdrawing polar substituents.From this correlation and a product analysis, the nature of the polar character at the transition state of the decomposition is discussed.
- Matsuyama, Kazuo,Higuchi, Yoshiki
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p. 259 - 265
(2007/10/02)
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- Reactions with Aziridines. 48. Friedel-Crafts Reactions with N-Sulfonated Aziridines and with Open-Chain Sulfonamides. Sulfonamides as Leaving Groups in Open-Chain Structures
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AlCl3-catalyzed reactions of N-sulfonylaziridines (C substituents given) 1a (no substituent), 4b (2-phenyl), 8b (2,3-diphenyl), and 11a-c (2,2-dimethyl) with neat benzene, toluene, or anisole proceeded rapidly without heating.The expected N-sulfonyl(aryle
- Stamm, Helmut,Onistschenko, Andreas,Buchholz, Berthold,Mall, Thomas
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p. 193 - 199
(2007/10/02)
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- STABILIZED CARBANIONS BY ALKYLLITHIUM-INDUCED DECARBOXYLATION OF NON-ENOLIZABLE CARBOXYLIC ACIDS. AN ANIONIC EQUIVALENT TO THE HUNSDIECKER REACTION
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Intermediate dianions formed by nucleophilic attac of metyllithium on "alpha"-phenyl or "alpha"- phenylthio carboxylate salts fragment in highly coordinating solvents to produce stabilized carbanions.Once formed, these anions may be conveniently functionalized with various electrophilicreagents.
- Gilday, John P.,Paquette, Leo A.
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p. 4505 - 4508
(2007/10/02)
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- Rearrangement of Benzylically Lithiated Methylaryl Alkyl Sulfones
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Lithiathion of appropriate methylaryl alkyl sulfones is followed by migration of the alkyl group from sulfur to the benzylic carbon.Product studies, relative reactivities, and crossover experiments are consistent with a radical-radical anion chain process for this rearrangement.
- Madaj, Edmund J.,Snyder, Donald M.,Truce, William E.
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p. 3466 - 3469
(2007/10/02)
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- Ketone-derived Peroxides. III. Decompositions of Cyclic Diperoxides derived from Dialkyl Ketones
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The decompositions of diperoxides from acetone, pentan-3-one, 1,5-diphenylpentan-3-one, pinacolone, benzyl methyl ketone and dibenzyl ketone have been studied.The yield of ketone decreases in this series, from 68percent with acetone to 1-2percent with dibenzyl ketone, i.e. with the increasing stability of the more stable radical fragment.The major products from the decompositions of diperoxides from the dibenzyl ketone and di(p-methylbenzyl) ketone were bibenzyl and 4,4'-dimethylbibenzyl respectively formed through coupling of benzyl radicals; crossover experiments showed that this was primarily an out-of-cage process.Most of the peroxides gave significant yields (5-20percent) of esters formed by an in-cage reaction between the alkyl radical and diacyl peroxide generated from decomposition of the biradical formed in the initial O-O bond homolysis of the peroxide.
- McCullough, Kevin J.,Morgan, Alistair R.,Nonhebel, Derek C.,Pauson, Peter L.
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p. 651 - 676
(2007/10/02)
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