Synthesis of 6,7-dihydro-5H-dibenzo[c,e]azepines and biaryls by palladium-catalyzed Ullmann reaction

A novel palladium-catalyzed Ullmann protocol is described for the synthesis of 6,7-dihydro-5H-dibenzo[c,e]azepines and biaryls. In the presence of Pd(OAc)2 and KOAc, intramolecular or intermolecular Ullmann coupling of aryl halides proceeds efficiently under ligand-free and aerobic conditions to afford the corresponding 6,7-dihydro-5H-dibenzo[c,e]azepines and biaryls in moderate to excellent yields.