- Dual Nickel- And Photoredox-Catalyzed Reductive Cross-Coupling of Aryl Halides with Dichloromethane via a Radical Process
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The first catalytic strategy to harness a new chloromethane radical from dichloromethane under dual Ni/photoredox catalytic conditions has been developed. Compared with traditional two-electron reductive process associated with metallic reductants, this method via a single-electron approach can proceed under exceptionally mild conditions (visible light, ambient temperature, no strong base) and exhibits complementary reactivity patterns. It affords a broad scope of many functional groups, including alkenyl, which suffers cyclopropanation in previous routes. The diarylmethane-d2 compounds can be readily available with this transformation.
- Xu, Tao,Xu, Wenhao,Zheng, Purui
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supporting information
(2020/11/13)
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- Benzylation of arenes with benzyl ethers promoted by the in situ prepared superacid BF3-H2O
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An efficient and environmentally friendly benzylation of arenes with benzyl ethers as benzyl donors using BF3-Et2O to generate in situ the superacid BF3-H2O as an efficient promotor has been described. A wide variety of functional groups have been investigated and found to be compatible to give the desired diarylmethanes in yields of up to 99%. The crucial role of the moisture content in this transformation has been demonstrated by detailed investigations. This journal is the Partner Organisations 2014.
- Li, Yu,Xiong, Yan,Li, Xueming,Ling, Xuege,Huang, Ruofeng,Zhang, Xiaohui,Yang, Jianchun
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supporting information
p. 2976 - 2981
(2014/06/10)
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- Facile one-pot palladium-catalyzed sequential coupling to diarylmethanes by using aryl methyl ketones as the methylene donors
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A novel palladium-catalyzed coupling reaction of an aryl methyl ketone with two molecules of an aryl halide to yield symmetric diarylmethanes is described. In the facile one-pot reaction, the aryl methyl ketone acts as a formal methylene donor. The experimental facts, including TLC monitoring, speculated intermediates as the raw materials, analysis of the cesium benzoate coproduct by ex situ IR spectroscopy, and the cross-coupling reactions of two different aryl halides, indicate a mechanism involving a palladium-catalyzed sequential two-step coupling process, in which the presence of a trace amount of H 2O is indispensable. The reaction is applicable to a broad spectrum of substrates and delivers the products in good to excellent yields. Access to unsymmetrical diarylmethanes with this method is also explored and various factors are discussed. An aryl methyl ketone is used as the methylene donor to couple with two molecules of an aryl halide for the synthesis of various symmetric diarylmethanes under palladium catalysis. The mechanism involves a two-step coupling process in which the presence of a trace amount of H 2O is indispensable. The cross-coupling to unsymmetrical diarylmethanes with this method is also explored. Copyright
- Wang, Xing,Liu, Lian-Hua,Shi, Jin-Hua,Peng, Ji,Tu, Hai-Yang,Zhang, Ai-Dong
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p. 6870 - 6877
(2013/11/06)
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- One-pot synthesis of symmetrical and unsymmetrical diarylmethanes via diborylmethane
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A one-pot synthesis of diarylmethanes from air-stable diborylmethane via the Suzuki-Miyaura cross-coupling reaction is described. The present approach realizes the synthesis of various symmetrical and unsymmetrical diarylmethanes in good to excellent yields.
- Endo, Kohei,Ishioka, Takafumi,Ohkubo, Takahiro,Shibata, Takanori
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p. 7223 - 7231
(2012/10/29)
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- Palladium-catalyzed cross-coupling alkylation of arenediazonium o-benzenedisulfonimides
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Arenediazonium o-benzenedisulfonimides were reacted with tetramethyltin, tetrabutyltin or trialkylboranes. The reactions, carried out in the presence of palladium(II) derivatives as precatalysts, gave the methylation and alkylation products with good over
- Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano
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p. 474 - 478
(2008/09/21)
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- Diamino compounds and methods for preparing them
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An object of the invention is to propose diamino compounds expressed by the following general formula (1) which are suitable to obtain a raw material, a polyimide resin, for a liquid crystal aligning film without any image sticking and with a high voltage holding ratio at from a low temperature to a high temperature as well as the preparation thereof: STR1
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- Carbon Acidity. 66. Equilibrium Ion Pair Acidities of Substituted Diphenylmethanes in Cyclohexylamine
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The pKCsCHA values are reported for a number of symmetrically meta- and para-substituted diphenylmethanes.The pKCsCHA values for the meta series (Me, 33.8; OMe, 32.7; F, 29.9; CF3, 28.9; Ph, 32.3; H, 33.4) give a normal Hammett plot with ρ = 9.69.The para series (Me, 35.1; OMe,37.6; Ph, 30.8; NMe2, 38.6; SPh, 28.8; CN, 23.0; SO2Me, 22.4) do not fit attempted correlations with ?, the Yukawa-Tsuno modifications, or dual substituent parameter approaches.Electron-donating groups are more anion destabilizing than in other reference systems. "Amphoteric" substituents, those that stabilize both anions and cations (phenyl, thio, etc.), cause special problems in generalized correlations.
- Streitwieser, Andrew Jr.,Vorpagel, Erich R.,Chen, Chia-Chung
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p. 6970 - 6975
(2007/10/02)
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- PREPARATION OF SOME TRIMETHYL- AND METHYLETHYLBIPHENYLS AND REACTIVITY OF AROMATIC HYDROCARBONS IN THE GOMBERG REACTION
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Trimethyl- and methylethylbiphenyls with the alkyl groups in the both phenyl rings have been prepared by the Gomberg reaction and identified by the capillary gas-liquid chromatography.Depending on choice of the aromatic hydrocarbon either individual isomers or their mixtures (three at the most) have been obtained which were contaminated with compounds of diarylmethane type in many cases.The methylethylbiphenyls have only been prepared as mixtures contaminated with diarylmethanes.These side products have been prepared by independent syntheses.A method has been developed for isolation and separation of mixtures of trimethyl- and methylethylbiphenyls from the reaction products containing tarry products.The method is suitable for preparation of small amounts of some analytical standards.The HMO method has been used for calculation of values of the radical superdelocalizabilities at individual centres in the molecules of o-, m- and p-xylene, toluene and ethylbenzene, and these values have been compared with composition of the Gomberg reaction products from these hydrocarbons.The competitive technique has been used for comparison of the reactivities of the mentioned aromatic substrates in the Gomberg reactions.
- Novrocik, Jan,Novrocikova, Marta,Titz, Milos
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p. 3140 - 3149
(2007/10/02)
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