Direct heteroarylation of 5-bromothiophen-2-ylpyridine and of 8-bromoquinoline via palladium-catalysed C–H bond activation: simpler access to heteroarylated nitrogen-based derivatives
The palladium-catalyseddirect heteroarylation of the pyridyl-containing substrates, 2-(5-bromothiophen-2-yl)pyridine and 8-bromoquinoline, proceeds in moderate to high yields with a variety of heteroarenes in the presence of 1–2 mol% of a palladium catalyst. This approach allows the access to polyheteroaromatics which are interesting building blocks as (N⁁C)-chelate ligands. The reaction proceeds
An Iron and Copper System Catalyzed C–H Arylation of Azoles with Arylboronic Acids
作者:Song-Lin Zhang、Wei-Ye Hu、Pei-Pei Wang
DOI:10.1055/s-0034-1379073
日期:——
An efficient, environmentally friendly, and economical new method for arylation reactions of azoles with arylboronic acids via copper-iron-catalyzed C-H and C-B bond activation has been developed. The protocol tolerates a series of functional groups, such as methoxy, nitro, cyano, chloro, and trifluoromethyl groups.
Oxidative NHC catalysis for base-free synthesis of benzoxazinones and benzoazoles by thermal activated NHCs precursor ionic liquid catalyst using air as oxidant
作者:Youkang Zhou、Wei Liu、Yuchen Liu、Jiali Guan、Jieying Yan、Jian-Jun Yuan、Duan-Jian Tao、Zhibin Song
DOI:10.1016/j.mcat.2020.111013
日期:2020.8
A reusable thermal activated NHC precursor ionic liquid catalyst ([BMIm](2)[WO4]) has been prepared and developed for the synthesis of nitrogen-containing heterocycles such as benzoxazinones and benzoazoles through imines activation. [BMIm](2)[WO4] exhibited the good activity for the base-free condensation and oxidative NHC catalysis tandem under air atmosphere. The catalyst can be recovered and reused for at least five runs in gram scale synthesis without any decrease in catalytic activity. Furthermore, the control experiments demonstrated that the reaction involved formation of aromatic aldimines, NHC-catalyzed oxidative formation of imidoyl azoliums and intramolecular cyclization to generate the product.