Efficient palladium-catalyzed direct arylation of azines and diazines using ligand- free conditions

The use of the palladium-catalyzed direct arylation was successfully tested on different electron-deficient heterocycles. The results demonstrate the effectiveness of the method based on the intramolecular coupling reaction providing polyazacyclic systems. This new application was obtained by using ligand-free conditions with the mixture of Pd(OAc)2 and TBAC as catalytic system. With suitable substrates different products arising from regioselective coupling were observed.