نتایج جستجو برای: Ullmann homocoupling reaction

تعداد نتایج: 412776  

A highly efficient Ullmann homocoupling reaction of aryl halides using palladium (II) phosphine-ylide complexes as homogenous pre-catalysts under aerobic conditions has been developed without the need for any chemical co‐reducing agents. The procedure is relatively mild and appears to have broad applicability, being useful for the homocoupling of both electron-deficient and electron-rich aryl h...

Journal: :Chemical communications 2011
Babak Karimi Farhad Kabiri Esfahani

We demonstrated an unprecedented example of Ullmann homocoupling reaction of aryl iodides over a novel recyclable gold catalyst comprising Au nanoparticles supported on a bifunctional periodic mesoporous organosilica (Au@PMO).

Journal: :Molecules 2013
Ulkü Yılmaz Selma Deniz Hasan Küçükbay Nihat Sireci

A number of novel benzimidazole derivatives 1-4 were synthesized and the catalytic activity of these compounds in a catalytic system consisting of a benzimidazolium salt/Pd(OAc)2/K2CO3 were investigated in the Suzuki-Miyaura and Ullmann type homocoupling reactions under microwave irradiation. We obtained both cross coupling and homocoupling products of pyridine and some side products such as di...

Journal: :Dalton transactions 2014
Wang Yao Wei-Jie Gong Hong-Xi Li Fei-Long Li Jun Gao Jian-Ping Lang

DMF-stabilized Au nanoparticles (NPs) with three different particle sizes were prepared by controlling the reaction temperatures and times. In the absence of any additional ligands, these Au NPs showed high catalytic activity in the Ullmann homocoupling of aryl iodides in DMF. The effects of Au particle size on the coupling reaction were investigated by the use of three Au catalysts with mean p...

Journal: :Chemical communications 2012
Gao Li Chao Liu Yu Lei Rongchao Jin

The Au(25)(SR)(18)/CeO(2) nanocluster catalyst showed high activity in the homocoupling of aryl iodides (e.g. up to 99.8% yield with iodobenzene) and excellent recyclability.

Journal: :ChemistrySelect 2022

A glycerol-based Deep Eutectic Solvent (DES) enables the Pd-catalyzed activation of (hetero)arylchlorides and promotes formation 2,2’-bipiyridines biaryls through an Ullmann-type homocoupling in smooth experimental conditions (80 °C) with Ca(OH)2 as a green base Pd/C heterogeneous catalyst. Noteworthy, coupling does not need addition external reducing agents, like metals, since glycerol present...

Journal: :Organic & biomolecular chemistry 2015
Sandip Murarka Juri Möbus Gerhard Erker Christian Mück-Lichtenfeld Armido Studer

The mechanism of the TEMPO mediated oxidative homo-coupling of aryl Grignard reagents is investigated in detail by experimental and computational studies. Experimental data reveal that the nitroxide-mediated homocoupling reaction of aryl Grignard reagents does not occur via free aryl radicals. Evidence for the presence of biaryl radical anions as intermediates in the coupling reaction is provid...

Journal: :Organic & biomolecular chemistry 2013
Jin-Biao Liu Lin Nie Hui Yan Li-Hua Jiang Jiang Weng Gui Lu

A novel procedure for the preparation of biaryl compounds by Pd-catalyzed homocoupling of N'-tosyl arylhydrazine has been described. N'-Tosyl arylhydrazine, as a readily available and stable coupling partner, demonstrated its generality in the homocoupling reactions. The scope of the reaction and possible mechanism have also been investigated.

2002
Aiwen Lei

Palladium-catalyzed homocoupling reaction of aryl boronic acids has been developed using a protocol similar to the well-documented crosscoupling reaction. -Halocarbonyl compounds are applied to initiate the reaction via oxidative addition to a palladium(0) species. The resulting palladium enolate halide can promote the double transmetallation. Reductive elimination generates the desire homocoup...

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