Pd(OAc)2‑Catalyzed Synthesis of Imidazo[1,2‑f]phenanthridines via a Sequential Ullmann Coupling and Oxidative Coupling Dehydrogenation

The Ullmann coupling and oxidative coupling dehydrogenation reactions have occurred sequentially, catalyzed by Pd­(OAc)2, which unexpectedly yielded fused imidazo­[1,2-f]­phenanthridine derivatives in good to high yields. Structural analysis of the intermediate and final products indicated that the protocol did not include C–H and N–H arylation.