Department of Chemistry, Università degli Studi Aldo Moro, Via Orabona 4, 70126 Bari, Italy.
J Org Chem. 2010 Jun 4;75(11):3908-11. doi: 10.1021/jo1005729.
An efficient and highly sustainable Ullmann-type homocoupling of bromo- and chloroarenes, including the more challenging electron-rich chloroarenes (e.g., 4-chloroanisole), catalyzed by in situ generated Pd colloids, is carried out in aqueous medium under relatively mild conditions (temperatures ranging from 40 to 90 degrees C). Glucose is used as a clean and renewable reductant, while tetrabutylammonium hydroxide (TBAOH) acts as base, surfactant, and phase-transfer agent, creating a favorable environment for the catalyst. Pd nanoparticle sizes, morphology, and chemical composition are ascertained by TEM and XPS analyses.
在温和的条件下(温度范围为 40 至 90 摄氏度),在水相介质中,通过原位生成的 Pd 胶体催化,实现了高效且可持续的溴代和氯代芳烃,包括更具挑战性的富电子氯代芳烃(例如 4-氯苯甲醚)的Ullmann 型同偶联。葡萄糖被用作清洁且可再生的还原剂,而四丁基氢氧化铵(TBAOH)则作为碱、表面活性剂和相转移剂,为催化剂创造了有利的环境。通过 TEM 和 XPS 分析确定了 Pd 纳米颗粒的大小、形态和化学组成。