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.
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。
A New and Simple Route to 3-Arylthiophenes
作者:Tyo Sone、Manabu Inoue、Kazuaki Sato
DOI:10.1246/bcsj.61.3779
日期:1988.10
3-Arylthiophenes were prepared from 2,5-dichlorothiophene in two steps. 2,5-Dichlorothiophene reacted regioselectively with various aromatic compounds in the presence of AlCl3 under mild conditions to give 4-aryl-2-chlorothiophenes. The latter compounds were easily converted to the corresponding 3-arylthiophenes by catalytic dechlorination in good yields.
Synthesis of 3,4′-Diaryl- and 4,4′-Diaryl-2,2′-bithienyls from 2,5-Dichlorothiophene
作者:Tyo Sone、Yasuhiro Umetsu、Kazuaki Sato
DOI:10.1246/bcsj.64.864
日期:1991.3
3,4′-Diaryl-, and 4,4′-diaryl-2,2′-bithienyls, new classes of mixed thiophene–arene oligomers, were synthesized from 2,5-dichlorothiophene via 4-aryl-2-chlorothiophene in three and two steps, respectively. Namely, a Friedel–Crafts type self-condensation of 4-aryl-2-chlorothiophene, followed by catalytic dechlorination, yielded unsymmetrical bithienyls. Homocoupling of 4-aryl-2-chlorothiophene using