Benzenesulfonyl chlorides: new reagents for access to alternative regioisomers in palladium-catalysed direct arylations of thiophenes
作者:Kedong Yuan、Henri Doucet
DOI:10.1039/c3sc52420e
日期:——
The palladium-catalysedcoupling of benzenesulfonylchlorides with thiophene derivatives allows regioselective access to β-arylated thiophenes. The reaction proceeds with easily accessible catalyst, base and substrates, without oxidant or ligand and tolerates a variety of substituents on both the benzene and thiophene moieties.
homogeneous palladium catalysts. Better yields were obtained with electron-deficient benzenesulfonylchlorides than with the electron-rich ones. Notably, useful substituents such as bromo or iodo on the benzenesulfonylchloride were tolerated, as no cleavage of the C-Br or C-I bonds was observed under these conditions. The use of Pd/C presents several advantages compared to the previously employed homogeneous
The first example of a regioselective β-arylation of benzo[b]thiophenes and thiophenes at room temperature with aryl iodides as coupling partners is reported. This methodology stands out for its operational simplicity: no prefunctionalization of either starting material is required, the reaction is insensitive to air and moisture, and it proceeds at room temperature. The mild conditions afford wide
报道了苯并[b]噻吩和噻吩在室温下以芳基碘作为偶联伙伴的区域选择性β-芳基化的第一个例子。这种方法因其操作简单而突出:不需要任何一种起始材料的预官能化,反应对空气和水分不敏感,并且在室温下进行。温和的条件提供了广泛的官能团耐受性,通常具有完全的区域选择性和高产率,从而形成高效的催化系统。包括 13C 和 2H KIE 在内的初步机理研究表明,该过程是通过噻吩双键上的协同碳钯化作用发生的,然后是碱基辅助的抗消除作用。
Para-coupling of phenols with C2/C3-substituted benzothiophene S-oxides
作者:Zhen He、Tony Biremond、Gregory J.P. Perry、David J. Procter
DOI:10.1016/j.tet.2020.131315
日期:2020.12
C2 and C3 substituted benzothiophenes are common structures in medicinal and materials chemistry. The cross-coupling of phenols with benzothiophenes is a useful route towards these important molecules. In this report we reveal an efficient C–H/C–H-type cross-coupling of benzothiophenes, activated as their S-oxides, with phenols to give C2/C3 arylated benzothiophenes. Whereas previous reports describe
Pd-Catalyzed β-Selective Direct C–H Bond Arylation of Thiophenes with Aryltrimethylsilanes
作者:Kenji Funaki、Tetsuo Sato、Shuichi Oi
DOI:10.1021/ol3029109
日期:2012.12.21
Direct arylation of thiophenes and benzothiophenes with aryltrimethylsilanes was effectively catalyzed by PdCl2(MeCN)2 in the presence of CuCl2 as an oxidant. The reaction preferentially occurred at the β-position of both thiophenes and benzothiophenes.