Metal‐Catalyzed C(sp ² )–H Bond Functionalization of Indolinone‐ and Indanone‐Type Chemical Platforms <i>En Route</i> Toward Late‐Stage Functionalization

C—H bond functionalization enabled by metal catalysis represents the most interesting entry for the development of cost‐effective transformations. As such, its implementation in late‐stage functionalization of pharmaceuticals is rising strong interest within the academic and industrial audiences. Nowadays, metal‐catalyzed aromatic C—H bond functionalizations are more developed than their aliphatic counterparts due to thermodynamic and kinetic considerations. However, most developments in metal‐catalyzed aromatic C—H bond functionalization have focused on mono‐functionalized, or at best, symmetric 1,2‐difunctionalized aromatics, which limits the selectivity issues to classical ortho/meta/para regioisomer patterns. However, natural products and drugs that contain aromatic groups typically comprise more elaborated functionalities at multiple positions. Of particular relevance are aromatic groups that are 1,2‐doubly fused with small, five‐membered rings featuring carbonyl groups, namely indolinones and indanones, such as phthalimides, isoindolinones, oxindoles, and isatins, just to mention a few. Conceiving metal‐catalyzed C—H bond functionalizations compatible to these biologically‐important building blocks has begun to strongly attract the interest of chemists in the last decades. Herein, we provide an exhaustive analysis of the current state‐of‐the‐art of the formation of carbon–carbon and carbon–heteroatom bonds via metal‐catalyzed C—H bond activation at indolinone‐ and indanone‐type of molecules while highlighting future research directions in this timely topic to go beyond the ortho/meta/para paradigm.