Iron-Catalyzed Intramolecular C(sp3)–H Amination toward C2-Spiroindolines

Abstract C2-Spiroindolines are valuable three-dimensional scaffolds, yet direct synthetic methods remain limited. Here, we report an iron-catalyzed intramolecular C(sp3)–H amination of readily accessible aryl azides and tetrazoles, enabling site-selective construction of C2-spiroindolines and their aza bioisosteres. The reaction accommodates diverse carbocyclic and heterocyclic motifs and affords products in up to 89% yield. Gram-scale synthesis and downstream derivatizations demonstrate synthetic utility, providing spirocyclic building blocks with potential applications in medicinal chemistry.