Wang Yongtao, Liu Jiaxin, Sun Wenjing, Zhou Yujia, Wang Xinyu, Hu Qixuan, Wen Zeyu, Yao Jia, Li Haoran
Department of Chemistry, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China.
Center of Chemistry for Frontier Technologies, ZJU-NHU United R&D Center, Zhejiang University, 866 Yuhangtang Rd, Hangzhou 310058, China.
J Org Chem. 2024 Feb 16;89(4):2440-2447. doi: 10.1021/acs.joc.3c02448. Epub 2024 Feb 2.
Aromatic C-H oxygenation is important in both industrial production and organic synthesis. Here we report a metal-free approach for phenol oxygenation with water as the oxygen source using oxoammonium salts as the renewable oxidant. Employing this protocol, various alkyl-substituted phenols were converted into benzoquinones in yields of 59-98%. On the basis of O-labeling and kinetic studies, the hydroxy-oxoammonium adduct was proposed to attack the aromatic ring similarly to electrophilic aromatic substitution. We suppose that the findings described here not only provide an efficient and highly selective protocol for aromatic C-H oxygenation but also may encourage further developments of possible transition-metal-free catalytic methods.
芳族C-H氧化在工业生产和有机合成中都很重要。在此，我们报道了一种无金属方法，该方法以水为氧源，使用氧鎓盐作为可再生氧化剂进行苯酚氧化。采用该方案，各种烷基取代的苯酚以59-98%的产率转化为苯醌。基于O标记和动力学研究，提出羟基氧鎓盐加合物与亲电芳族取代类似地进攻芳环。我们认为，此处所述的发现不仅为芳族C-H氧化提供了一种高效且高选择性的方案，而且可能会促进无过渡金属催化方法的进一步发展。
