Visible-Light-Induced Palladium-Mediated Allylic C–H Alkylation Reaction

Direct C-H alkylation is one of the most important C-C bond formation events and is crucial to the efficient assembly of functionalized carbon skeletons in synthetic chemistry. We report herein a photoinduced palladium-catalyzed strategy for the direct alkylation of allylic C-H bonds. The success of this transformation relies on the use of 2-bromo-1,3-dimethylbenzene as a hydrogen atom transfer (HAT) mediator, in combination with a carbon nucleophile, facilitated by a palladium catalyst activated by blue light. Unlike classical Pd(II/0) pathways, this approach leverages the versatile reactivity of Pd(0/I/II) species through visible-light excitation, establishing a robust foundation for the feasibility of this synthetic methodology.