Sterically Encumbered Tetraarylimidazolium Carbene Pd-PEPPSI Complexes: Highly Efficient Direct Arylation of Imidazoles with Aryl Bromides under Aerobic Conditions

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• 作者：Xu-Xian He ; Yinwu Li ; Bei-Bei Ma ; Zhuofeng Ke ; Feng-Shou Liu
• 刊名：Organometallics
• 出版年：2016
• 出版时间：August 22, 2016
• 年：2016
• 卷：35
• 期：16
• 页码：2655-2663
• 全文大小：558K
• 年卷期：0
• ISSN：1520-6041

文摘

A series of sterically encumbered tetraarylimidazolium carbene Pd-PEPPSI complexes were conveniently prepared and fully characterized. These sterically encumbered Pd-PEPPSI complexes act as active precatalysts for the direct arylation of imidazoles with aryl bromides under aerobic conditions. The catalytic performance of Pd-PEPPSI complexes in cross-coupling processes is investigated. Under the optimal protocols, the cross-coupling reactions regioselectively produced C5-arylation products in moderate to excellent yields, which could tolerate a wide range of functional aryl bromides.