Photoredox/Cobalt-Catalyzed C(sp<sup>3</sup>)–H Bond Functionalization toward Phenanthrene Skeletons with Hydrogen Evolution
Jia‐Dong Guo, Xiu‐Long Yang, Bin Chen, Chen‐Ho Tung, Li‐Zhu Wu
Abstract
The first example of photoredox strategy for synthesis of phenanthrene skeletons through C(sp3)–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 a-carbonyl radical for highly substituted 10-phenanthrenols in good to excellent yields.
Topics & Concepts
ChemistryCatalysisPhenanthreneTautomerEnolMoietyPhotoredox catalysisSurface modificationPhotochemistryCobaltPhotocatalysisSubstrate (aquarium)Electron transferCombinatorial chemistryMedicinal chemistryOrganic chemistryOceanographyGeologyPhysical chemistryCatalytic C–H Functionalization MethodsRadical Photochemical ReactionsSulfur-Based Synthesis Techniques