Synergistic Amino/Amide-Directed C5–H Annulation toward Polycyclic Coumarin Heterocycles

A palladium-catalyzed annulation strategy for the synthesis of polycyclic heteroaromatic compounds incorporating a coumarin scaffold is developed. A key feature of this transformation is the use of a bidentate directing group composed of an amino and amide moiety, which enables precise control over periselective C-H activation and subsequent annulation. This robust protocol tolerates diverse coupling partners and delivers a broad range of π-extended, densely functionalized polycyclic frameworks in a single step. The resulting scaffolds represent privileged, yet underexplored, motifs with potential relevance to pharmaceutical and materials chemistry. Density functional theory (DFT) calculations were performed to corroborate the proposed reaction mechanism.