Guo Jia-Dong, Yang Xiu-Long, Chen Bin, Tung Chen-Ho, Wu Li-Zhu
Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, P.R. China.
School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
Org Lett. 2020 Dec 18;22(24):9627-9632. doi: 10.1021/acs.orglett.0c03665. Epub 2020 Dec 8.
The first example of photoredox strategy for synthesis of phenanthrene skeletons through C(sp)-H functionalization under external oxidant-free conditions is achieved. This transformation relies on the keto-enol tautomerism of 1,3 dicarbonyl moiety, i.e., the enol form of 1,3-dicarbonyl derivatives with relatively lower oxidation potential can be activated by the excited acridinium photocatalyst. The electron and proton eliminated from the substrate are immediately captured by a cobaloxime catalyst to exclusively afford -carbonyl radical for highly substituted 10-phenanthrenols in good to excellent yields.
实现了在无外部氧化剂条件下通过C(sp)-H官能化合成菲骨架的光氧化还原策略的首个实例。这种转化依赖于1,3-二羰基部分的酮-烯醇互变异构，即氧化电位相对较低的1,3-二羰基衍生物的烯醇形式可被激发的吖啶鎓光催化剂活化。从底物消除的电子和质子立即被钴肟催化剂捕获，以高收率专一性地生成用于高度取代的10-菲醇的羰基自由基。
