F for fast: The perfluorinated solvent C6F14 is the key to a new variant of the Balz–Schiemann reaction for the synthesis of fluorinated arenes. Triazenes are converted into fluoroarenes under mild conditions on a support and in solution (see scheme). The method is straightforward and inexpensive, and yields previously difficult‐to‐prepare fluoroarenes in high purity.
快速反应的F:全氟化溶剂C 6 F 14是Balz-Schiemann反应新变体(用于合成氟化芳烃)的关键。在温和的条件下,将三氮烯在载体和溶液中转化为氟代芳烃(参见方案)。该方法简便易行且价格便宜,并且可以产生以前难以制备的高纯度氟代芳烃。
Carboxymethylcellulose-supported palladium nanoparticles generated <i>in situ</i>
from palladium(II) carboxymethylcellulose as an efficient and reusable catalyst for ligand- and base-free Heck-Matsuda and Suzuki-Miyaura couplings
作者:Jinlong Xiao、Zhangxiu Lu、Zhipeng Li、Yiqun Li
DOI:10.1002/aoc.3346
日期:2015.9
A novel palladium(II) carboxymethylcellulose (CMC‐PdII) was prepared by direct metathesis from sodium carboxymethylcellulose and PdCl2 in aqueous solution. Its catalytic activities were explored for Heck–Matsuda reactions of aryldiazoniumtetrafluoroborate with olefins, and Suzuki–Miyaura couplings of aryldiazoniumtetrafluoroborate with arylboronic acid. Both reactions proceeded at room temperature
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。