Photouranium-Catalyzed C–F Activation Hydroxylation via Water Splitting
Xiu Yan Zhao, Leiyang Bai, Jiayi Li, Xuefeng Jiang
Abstract
The C–F bond is the strongest covalent single bond (126 kcal/mol) in carbon-centered bonds, in which the highest electronegativity of fluorine (χ = 4) gives rise to the shortest bond length (1.38 Å) and the smallest van der Waals radius ( r w = 1.47 Å), resulting in enormous challenges for activation and transformation. Herein, C–F conversion was realized via photouranium-catalyzed hydroxylation of unactivated aryl fluorides using water as a hydroxyl source to deliver multifunctional phenols under ambient conditions. The activation featured cascade sequences of single electron transfer (SET)/hydrogen atom transfer (HAT)/oxygen atom transfer (OAT), highly integrated from the excited uranyl cation. The *UO 2 2+ prompted water splitting under mild photoexcitation, caging the active oxygen in a peroxo-bridged manner for the critical OAT process and releasing hydrogen via the HAT process.