Highly selective photocatalytic oxidation of benzylic C-H bonds in alkylbenzenes to ketones.

This study develops a photocatalytic system based on non-metallic tubular hollow-structured g-C3N4 (HT-CN), which achieves highly selective oxidation of benzylic C-H bonds in alkylbenzenes to ketones by introducing lithium bromide (LiBr) as a dual-functional mediator. Innovatively, the system employs bromine radicals (Br˙) generated via photoinduced dissociation of LiBr for pre-activation of benzylic C-H bonds. Combined with the synergistic oxidation effect of photogenerated singlet oxygen (1O2) from HT-CN, this strategy successfully addresses the challenges of poor selectivity, low efficiency, and limited substrate generality in conventional methods under mild conditions: room temperature, visible-light irradiation, and oxygen atmosphere, providing a novel approach for green synthesis of aromatic ketones.