Transition-metal-catalyzed alkene-relayed intermolecular C–H activation

Alkene-relayed C-H activation constitutes a novel strategy for selective C-H functionalization. In this context, intermolecular reactions that incorporate alkenes into the final products are of significant interest. During these transformations, alkenes not only act as a relay for C-H activation but also serve as carbon synthons, becoming integral components of the product architecture. This dual role enhances their utility in transition-metal-catalyzed C-H activation, broadening the scope of synthetic applications. This review systematically summarizes such alkene-relayed C-H functionalization reactions. The discussed reactions are categorized based on alkene type, metal catalyst, and transformation class, with detailed mechanistic insights provided for representative examples. Additionally, the review highlights current challenges and future prospects for research in this evolving field.