Palladium‐Catalyzed Domino Double N‐Arylations (Inter‐ and Intramolecular) of 1,2‐Diamino(hetero)arenes with o,o′‐Dihalo(hetero)arenes for the Synthesis of Phenazines and Pyridoquinoxalines

Domino reactions for the synthesis of phenazines have been developed that start from 1,2‐diaminoarenes and 1,2‐dihaloarenes and proceed through palladium‐catalyzed double N‐arylations (inter‐ and intramolecular) followed by an in situ oxidation. A variety of functional groups, which include base‐sensitive groups, were well tolerated under the optimized reaction conditions to afford phenazines in good to excellent yields. The protocol was extended to the synthesis of pyridoquinoxalines by employing either o‐phenylenediamines and 2,3‐dihalopyridines or 1,2‐diaminopyridines and 1,2‐dihaloarenes.