Pd(OAc)₂‑Catalyzed Approach to Phenanthridin-6(5<i>H</i>)‑one Skeletons

Herein, we present a Pd(OAc)2/Dppp-catalyzed synthesis of 4-arylphenanthridinones from 2-bromobenzamides and iodobenzene, which undergoes successive Ullman cross-coupling, C–H activation, and oxidative coupling dehydrogenation process. The presented methods offer an adaptable and modular synthesis route for efficiently producing a wide array of valuable phenanthridiones, demonstrating exceptional compatibility with functional groups. Alternatively, a 1:1 cross-coupling reaction utilizing an intramolecular norbornene moiety as the ligand resulted in phenanthridinones through N-arylation and C–H activation.