†College of Chemistry and Molecular Sciences, the Institute for Advanced Studies (IAS), Wuhan University, Wuhan 430072, People's Republic of China.
‡Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
Org Lett. 2015 May 1;17(9):2174-7. doi: 10.1021/acs.orglett.5b00775. Epub 2015 Apr 10.
A novel oxidative C-H/C-H cross-coupling reaction between electron-rich arenes and alkenes is established utilizing FeCl3 as the catalyst and DDQ as the oxidant. Interestingly, direct arylation products are obtained with diaryl-ethylenes and double arylation products are obtained with styrene derivatives, which show high chemoselectivity and good substrate scope. A radical trapping experiment and EPR (electron paramagnetic resonance) experiments indicate that this reaction proceeds through a radical pathway in which DDQ plays a key role in the aryl radical formation. XAFS (X-ray absorption fine structure) experiments reveal that the oxidation state of the iron catalyst does not change during the reaction, suggesting that FeCl3 might be used as a Lewis acid. Finally, a detailed mechanism is proposed for this transformation.
建立了一种新型的铁氯化物 3 作为催化剂和 DDQ 作为氧化剂的富电子芳环和烯烃之间的氧化 C-H/C-H 交叉偶联反应。有趣的是，二芳基乙烯得到直接芳基化产物，而苯乙烯衍生物得到双芳基化产物，表现出高化学选择性和良好的底物范围。自由基捕获实验和 EPR（电子顺磁共振）实验表明，该反应通过自由基途径进行，其中 DDQ 在芳基自由基形成中起关键作用。XAFS（X 射线吸收精细结构）实验表明，反应过程中铁催化剂的氧化态没有变化，这表明 FeCl3 可能被用作路易斯酸。最后，提出了这种转化的详细机理。
