Palladium?Catalyzed Direct Diarylation of 2?Benzyl?1,2,3?triazole: a Simple Access to 4?Aryl? or 4,5?Diaryl?2?benzyl?1,2,3?triazoles and Phenanthro[9,10? d ][1,2,3]triazoles

The reactivity of 2-benzyl-1,2,3-triazole in palladium-catalyzed direct arylation was studied. reaction conditions for the selective synthesis 2-benzyl-4-aryl-1,2,3-triazoles moderate to high yields using phosphine-free Pd(OAc)2 catalyst and inexpensive KOAc base have been found. Then, from these 4-aryl-1,2,3-triazoles, C?H bond functionalization C5-position allowed corresponding 4,5-diarylated 2-benzyl-1,2,3-triazoles. This 4,5-diarylation successfully applied straightforward building ?-extended polycyclic heteroaromatic structures phenanthro[9,10-d][1,2,3]triazoles through Pd-catalyzed C4- C5-intermolecular arylations followed by intramolecular arylation.