Cobalt-Catalyzed Oxidative C−H/C−H Cross-Coupling between Two Heteroarenes

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• 作者：Guangying Tan ; Shuang He ; Xiaolei Huang ; Xingrong Liao ; Yangyang Cheng and Prof. Dr. Jingsong You
• 刊名：Angewandte Chemie
• 出版年：2016
• 出版时间：August 22, 2016
• 年：2016
• 卷：128
• 期：35
• 页码：10570-10574
• 全文大小：638K
• ISSN：1521-3757

文摘

The first example of cobalt-catalyzed oxidative C−H/C−H cross-coupling between two heteroarenes is reported, which exhibits a broad substrate scope and a high tolerance level for sensitive functional groups. When the amount of Co(OAc)₂⋅4 H₂O is reduced from 6.0 to 0.5 mol %, an excellent yield is still obtained at an elevated temperature with a prolonged reaction time. The method can be extended to the reaction between an arene and a heteroarene. It is worth noting that the Ag₂CO₃ oxidant is renewable. Preliminary mechanistic studies by radical trapping experiments, hydrogen/deuterium exchange experiments, kinetic isotope effect, electron paramagnetic resonance (EPR), and high resolution mass spectrometry (HRMS) suggest that a single electron transfer (SET) pathway is operative, which is distinctly different from the dual C−H bond activation pathway that the well-described oxidative C−H/C−H cross-coupling reactions between two heteroarenes typically undergo.