CH Functionalization and Cyclization Reactions Using Hypervalent Iodine Reagents: A Review on Synthetic Applications

Using hypervalent iodine reagents as a mediator or catalyst in CH functionalization and cyclization reactions has emerged as a powerful strategy in organic synthesis. This review exhaustively probes the recent advancements in this field, focusing on copious reactions enabled by hypervalent iodine (III/V) reagents. The versatility of iodine as a promoter in numerous transformations, including CH activation, functionalization, and cyclization processes is highlighted. The general mechanistic pathway of iodine in mediating these transformations, along with the underlying principles governing the selectivity and reactivity of these transformation processes, is discussed. Furthermore, reactions leading to the synthetic utility and applicability of iodine-catalyzed/promoted CH functionalization and cyclization reactions in synthesizing complex natural products and biologically active molecules are showcased. Overall, this review provides valuable insight for researchers and pharmacists interested in harnessing the potential of hypervalent iodine in developing sustainable and efficacious synthetic methodologies. © 2025 Elsevier B.V., All rights reserved.