- Dual Ligand-Enabled Nondirected C-H Cyanation of Arenes
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Aromatic nitriles are key structural units in organic chemistry and, therefore, highly attractive targets for C-H activation. Herein, the development of an arene-limited, nondirected C-H cyanation based on the use of two cooperatively acting commercially available ligands is reported. The reaction enables the cyanation of arenes by C-H activation in the absence of directing groups and is therefore complementary to established approaches.
- Chen, Hao,Mondal, Arup,Wedi, Philipp,Van Gemmeren, Manuel
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p. 1979 - 1984
(2019/02/19)
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- 1,4-Dicarbofunctionalization of 4-Fluoroaryl Grignard and Lithium Reagents with Disubstituted Malononitriles
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An efficient one-pot 1,4-dicarbofunctionalization of 4-fluoroaryl Grignard or lithium reagents with 2,2-disubstituted malononitriles is described. The reaction proceeds by sequential transnitrilation and SNAr reactions. Commercial Grignard solutions, Grignard reagents prepared in situ by halogen/magnesium exchange with i-PrMgCl, or aryllithium reagents prepared in situ by bromine/lithium exchange with n-BuLi are compatible with the reaction conditions. Moreover, 2,2-disubstituted malononitriles of diverse structures are accommodated. The reaction provides a unique approach to 1,4-dicarbofunctionalization of activated arenes in a tandem, one-pot transformation.
- Malapit, Christian A.,Luvaga, Irungu K.,Reeves, Jonathan T.,Volchkov, Ivan,Busacca, Carl A.,Howell, Amy R.,Senanayake, Chris H.
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p. 4993 - 4997
(2017/05/12)
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- Phosphine-Ligated Palladium Sulfonate Palladacycles
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Described are palladium precatalysts, and methods of making and using them. The palladium precatalysts show improved stability and improved reactivity in comparison to previously-described palladium precatalysts.
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Paragraph 0059; 0301
(2014/01/08)
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- One-pot, two-step, microwave-assisted palladium-catalyzed conversion of aryl alcohols to aryl fluorides via aryl nonaflates
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A convenient procedure for converting aryl alcohols to aryl fluorides via aryl nonafluorobutylsulfonates (ArONf) is presented. Moderate to good one-pot, two-step yields were achieved by this nonaflation and microwave-assisted, palladium-catalyzed fluorination sequence. The reductive elimination step was investigated by DFT calculations to compare fluorination with chlorination, proving a larger thermodynamic driving force for the aryl fluoride product. Finally, a key aryl fluoride intermediate for the synthesis of a potent HCV NS3 protease inhibitor was smoothly prepared with the novel protocol.
- Wannberg, Johan,Wallinder, Charlotta,Uenluesoy, Meltem,Skoeld, Christian,Larhed, Mats
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p. 4184 - 4189
(2013/05/22)
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- Accelerating palladium-catalyzed C-F bond formation: Use of a microflow packed-bed reactor
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A flow process for Pd-catalyzed C-F bond formation is described. A microreactor with a packed-bed design allows for easy handling of large quantities of insoluble CsF with precise control over reaction times, efficient mixing, and the ability to safely handle elevated temperatures and pressures. A variety of aryl triflates, including heteroaryl ones, were converted into aryl fluorides in short reaction times (see scheme).
- Noel, Timothy,Maimone, Thomas J.,Buchwald, Stephen L.
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supporting information; experimental part
p. 8900 - 8903
(2011/10/19)
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- Cyanation of arenes via iridium-catalyzed borylation
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We report a method to conduct one-pot meta cyanation of arenes by iridium-catalyzed C-H borylation and copper-mediated cyanation of the resulting arylboronate esters. This process relies on a method to conduct the cyanation of arylboronic esters, and conditions for this new transformation are reported. Conditions for the copper-mediated cyanation of arylboronic acids are also reported. By the resulting sequence of borylation and cyanation, 1,3-disubstituted and 1,2,3-trisubstituted arenes and heteroarenes containing halide, ketone, ester, amide, and protected alcohol functionalities are converted to the corresponding meta-substituted aryl nitriles. The utility of this methodology is demonstrated through the conversion of a protected 2,6-disubstituted phenol to 4-cyano-2,6-dimethylphenol, which is an intermediate in the synthesis of the pharmaceutical etravirine. The utility of the method is further demonstrated by the conversion of 3-chloro-5-methylbenzonitrile, produced through the one-pot C-H borylation and cyanation sequence, to the corresponding 3,5-disubstituted aldehydes, ketones, amides, carboxylic acids, tetrazoles, and benzylamines.
- Liskey, Carl W.,Liao, Xuebin,Hartwig, John F.
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supporting information; experimental part
p. 11389 - 11391
(2010/10/01)
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