Air- and moisture-stable Xantphos-ligated palladium dialkyl complex as a precatalyst for cross-coupling reactions
作者:Rina Takahashi、Koji Kubota、Hajime Ito
DOI:10.1039/c9cc06946a
日期:——
xantphos has been employed in a variety of palladium-catalyzed cross-couplingreactions, there has been little progress in developing Xantphos-ligated precatalysts. In this report, we describe a Xantphos-ligated palladium dialkyl complex that acts as a powerful precatalyst for C-N, C-S, and C-C cross-couplingreactions. This precatalyst is air- and moisture stable but can be thermally activated in the
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。
Photocatalyst-free, Visible Light Driven, Gold Promoted Suzuki Synthesis of (Hetero)biaryls
作者:Christopher Sauer、Yang Liu、Assunta De Nisi、Stefano Protti、Maurizio Fagnoni、Marco Bandini
DOI:10.1002/cctc.201701436
日期:2017.12.20
A visible‐lightdrivenSuzuki cross‐coupling reaction was performed with colored and bench‐stable arylazosulfones in the presence of Ph3PAuCl (5 mol %) as the catalyst. The absence of a photocatalyst, along with the use of commercially available and easy‐to‐handle arylboronic acids underline the novelty and synthetic usefulness of the protocol. A reaction mechanism involving the generation of an aryl
Palladium-Catalyzed Phosphine-Free Direct C–H Arylation of Benzothiophenes and Benzofurans Involving MIDA Boronates
作者:Mengmeng Huang、Yangjie Wu、Zhiwei Wang、Yabo Li、Beiqi Yan
DOI:10.1055/s-0034-1379606
日期:——
With high regioselectivity, a series of benzoheterocyclic compounds were synthesized via palladiium-catalyzed phosphine-free C-H arylation of benzothiophenes/benzofurans with aryl MIDA boronates at 30-50 degrees C in moderate to excellent yields. MIDA boronates were used in C-H arylation of heterocycles for the first time. Under the optimal conditions, the benzothiophenes could be transformed into the beta-arylbenzothiophenes, and the benzofurans gave only alpha-aryl-substituted products.