Recent advances in allylic and vinylic C-H bond functionalization of simple alkenes via visible-light photocatalysis

The selective functionalization of allylic and vinylic C-H bonds in simple alkenes represents a powerful yet challenging strategy for the direct construction of value-added molecular architectures from readily available feedstocks. Traditional approaches to allylic and vinylic C-H bond activation often rely on harsh reaction conditions, stoichiometric oxidants, or transition-metal catalysts, limiting functional-group tolerance and sustainability. In recent years, visible-light photocatalysis has emerged as a mild and versatile platform for allylic and vinylic C-H bond functionalization via single-electron transfer, energy transfer, and hydrogen-atom-transfer pathways. This approach allows the controlled generation of several radical intermediates under ambient conditions, facilitating a broad range of transformations. In this review, recent advances in allylic and vinylic C-H bond functionalization are introduced together with representative examples. By organizing recent reports according to their underlying mechanistic pathways, this review aims to provide informative references and insights for further research on alkene functionalization via visible-light photocatalysis.