- Transition-Metal-Free Cross-Coupling by Using Tertiary Benzylic Organoboronates
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The transition-metal-free cross-coupling of alkyl or aryl electrophiles by using tertiary benzylic organoboronates is reported. This reaction involves the generation of tertiary alkyl anions from organoboronates in the presence of an alkoxide base and then their substitution reactions. This protocol allows the simple and efficient construction of quaternary carbon centers.
- Takeda, Mitsutaka,Nagao, Kazunori,Ohmiya, Hirohisa
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supporting information
p. 22460 - 22464
(2020/10/12)
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- Metalation of toluene and cumene with alkali metal-crown ether complexes
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Metalation of toluene and isopropylbenzene with alkali metal-crown ether complexes led to the corresponding α-metalated alkylbenzenes. Treatment of the latter in succession with solid carbon dioxide, water, and hydrochloric acid gave carboxylic or dicarboxylic acids in 65-78% yield. Metalation of isopropylbenzene with sodium or potassium crown ether complexes above 90°C was accompanied by cleavage of the polyether ring with formation of organometallic compounds which then reacted with isopropylbenzene to produce 2-sodio(potassio)-2-phenylpropane and open-chain oligoether.
- Shabanov,Seidov,Gasanova,Kakhramanova,Gasanova
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experimental part
p. 26 - 29
(2009/06/28)
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- Production of benzyllithium, benzylsodium, and polyphenylene paradimethylene
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A process for producing benzyllithium, benzylsodium and polyphenylene paradimethylene and analogs comprising dissolving toluene in an aprotic polar solvent in which toluene is more acidic than water, such as DMSO, under an inert atmosphere, such as argon, adding an alkali metal hydroxide, such as lithium or sodium hydroxide, to form the alkali metal anion of the benzyl cation and water then removing the solvent and water to obtain the solid alkali metal alpha-carbon toluene compound, which is best stored under hexane. This process also relating to toluene analogs such as parachloro toluene which thereby yields parachloro alkali metal alpha-carbon toluene which is then polymerized by heating with a suitable high-boiling solvent, such as dibutyl ether or dimethoxy ethane in the presence of a copper catalyst, such as copper sulfate or finely divided copper metal at approximately 170C for 5 hours to form polyphenylene paradimethylene. This process having the advantage of using alkali metal hydroxides instead of elemental alkali metals, a reaction occurring at ordinary temperatures, and a lower cost of the product. This process also allowing the economical production of polyphenylene paradimethylene which is not currently being manufactured.
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Page/Page column 1
(2008/06/13)
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- Particles comprising amphiphilic copolymers, having a crosslinked shell domain and an interior core domain, useful for pharmaceutical and other applications
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Provided are particles comprising amphiphilic copolymers, having a crosslinked shell domain and an interior core domain. Also provided are compositions comprising such particles, including pharmaceutical compositions, methods of making the present particles, and methods of using such particles, for example for delivery of pharmaceutically active agents.
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- Acidity of Dibasic Acids I: the Second Acidity Constant of 9,10-Dihydroanthracene and its 9,10-Substituted Derivatives: Effect of Substituent and Counter Ion
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The second equilibrium ion pair acidity constants (pK2) of 9,10-dihydroanthracene, 9-phenyl-9,10-dihydroanthracene, 9,10-diphenyl-9,10-dihydroanthracene and 9-cyano-9,10-dihydroanthracene with sodium, potassium and rubidium have been determined in tetrahydrofuran (THF) at 25 deg C in the concentration range 10-5-10-2 mol dm-3.Equilibria were monitored by UV-VIS and 1H NMR spectroscopies and the spectra of the dimetallic and monometallic salts reported.The dimetallic salts of all the dibasic carbon acids studied behave as contact ion pairs in THF.The pK2 of 9,10-dihydroanthracene is insensitive to substituent effect but is strongly dependent on the cation.
- Shapiro, Israel O.,Nir, Malka,Hoffman, Roy E.,Rabinovitz, Mordecai
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p. 1519 - 1524
(2007/10/02)
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