Iron-catalyzed radical reactions: recent progress in organic synthesis

Iron-catalyzed radical reactions provide a powerful and sustainable approach in organic synthesis, offering cost-effective and environmentally benign alternatives to precious-metal catalysts. Its redox versatility allows controlled radical generation under mild conditions, enabling diverse transformations. Iron activates C-X bonds via halogen abstraction or single-electron transfer (SET) and functions as a bifunctional Lewis acid through Fe-σ and Fe-π interactions, further broadening its reactivity. These features have expanded applications in pharmaceuticals, natural products, and functional materials. Coupling iron catalysis with photoredox methods enhances both reaction scope and sustainability. This review surveys recent advances in cross-coupling, C-H functionalization, cyclization, decarboxylation, amination, and heterocycle synthesis, organized by radical generation strategies, and concludes with perspectives on future developments.