Transition Metal-Catalyzed Direct C(sp ³ )–H Functionalization Reactions of Aliphatic Carboxylic Acids

)-H functionalization reactions, enabled by the carboxylic acid group, spanning contributions from 1991 to 2025. It thoroughly examines the distinct mechanistic manifolds for the C-H functionalization of carboxylic acids, systematically comparing these modes of reactivity and their respective challenges/opportunities. In addition, the discussion encompasses reaction design, substrate scopes, mechanistic features, and a critical assessment of the current methodologies, providing readers with valuable insights to guide future research efforts.