DMAP‐Catalyzed [4 + 3] Spiroannulation of Ninhydrin‐Derived MBH Carbonates with Acyclic Azadienes: Efficient Access to Multisubstituted Spiro[indanone‐azepine] Scaffolds

Abstract Indanedione‐containing spirocyclic derivatives are of significant interest in medicinal chemistry. However, spirofusion of indanediones with seven‐membered rings remains relatively unexplored. In this study, we report an efficient DMAP‐catalyzed [4 + 3] annulation of ninhydrin‐derived MBH carbonates with acyclic azadienes, providing a series of polysubstituted, pharmacologically interesting spiro[indanone‐azepine] derivatives in good to excellent yields (up to 98%) under mild conditons. The method is practical, tolerant of various functional groups, and allows for the rapid synthesis of a diverse range of products from simple, readily available starting materials. The successful scale‐up reaction and derivatization of the product further demonstrate the practicality and reliability of this method.