Synthesis of biaryls via the Suzuki-Miyauracoupling (SMC) reaction using nitroarenes as an electrophilic coupling partners is described. Mechanistic studies have revealed that the catalytic cycle of this reaction is initiated by the cleavage of the aryl-nitro (Ar-NO2) bond by palladium, which represents an unprecedented elemental reaction.
Palladium-catalyzed denitrative Suzuki coupling of nitroarenes using 2-aryl-5-(2,4,6-triisopropylphenyl)-2,3-imidazolylidene[1,5-a]pyridines as the ligands is described. The key to success is the use of the NHC ligands which show strong donating ability and suitable steric hindrance allowing the successful oxidative addition of Ar–NO2 bonds. Both aromatic and aliphatic boronic acids are tolerated,
描述了使用2-芳基-5-(2,4,6-三异丙基苯基)-2,3-咪唑基亚甲基[1,5- a ]吡啶作为配体的钯催化硝基芳烃的反硝化Suzuki偶联。成功的关键是使用NHC配体,该配体显示出强大的供体能力和适当的空间位阻,可以成功地氧化添加Ar–NO 2键。芳族和脂族硼酸都可以被接受,并且以良好或优异的收率获得了各种联苯和烷基芳烃。
1,3-Phenylene-bis-(1<i>H</i>)-tetrazole Pincer Ligand for Palladium-Catalyzed Suzuki Cross-Coupling Reactions of Arylhalides with Arylboronic Acids
作者:Chang Ho Oh、Arun Kumar Gupta、Chul Yun Rim
DOI:10.1055/s-2004-831303
日期:——
1,3-Phenylene-bis-(1H)-tetrazole pincer ligand was synthesized by the reaction of 1, 3-phenylenediamine, sodium azide and triethyl orthoformate in acetic acid and successfully used in Suzuki cross coupling reactions of aryl halides with aryl boronic acids.
In a cross coupling reaction, in a case where a halogen atom is selected as the leaving group of the raw material compound, a harmful halogen waste forms as a by-product after the reaction, and disposal of the waste liquid is complicated and environmental burden is high. In a carbon-hydrogen activation cross coupling reaction which requires no halogen atom as the leaving group, although no halogen waste forms as a by-product, the reaction substrate is considerably restricted, and the reaction remains a limited molecular construction method.
A method for producing an aromatic compound, which comprises subjecting an aromatic nitro compound and a boronic acid compound to a cross coupling reaction in the presence of a metal catalyst.