Recent Advances in the Borylation of Spirocyclic and Bicyclic Frameworks: Synthetic Strategies and Applications in Medicinal Chemistry

In modern drug discovery, significant focus is placed on modulating the physical and biological properties of small molecules to address emerging therapeutic challenges, such as drug resistance and target selectivity. In this context, bicyclic and spiro compounds have gained importance as privileged scaffolds owing to their well‐defined three‐dimensional structures and intrinsic rigidity. These structural features enable precise conformational control, thereby enhancing key parameters such as binding affinity, selectivity, and pharmacokinetic properties. Despite their significance, the selective functionalization of these strained systems remains challenging due to steric congestion, ring strain, and limited accessibility to reactive regions. In this regard, organoboron chemistry has emerged as an effective platform for the site‐selective installation of versatile boron functionalities, allowing late‐stage functionalization of strained frameworks such as bicyclo and spiro compounds. Herein, we present a critical analysis of recent advances in the borylation of bicyclic and spirocyclic frameworks, with a particular emphasis on mechanistic aspects, catalyst‐controlled reactivity, and late‐stage modifications. Furthermore, a comparative assessment across different scaffold classes reveals key structure‐reactivity relationships and illustrates current limitations of these protocols. These insights provide a foundation for the rational design of improved catalytic systems and the expansion of synthetic applications of strained molecular architectures.