Assembly of 1,2,3-triazole-fused polycyclic compounds by palladium-catalyzed C-H bond activation

A palladium-catalyzed protocol for the synthesis of 1,2,3-triazole-fused heterocycles, such as 1,4,5,6-tetrahydrobenzo[c][1,2,3]triazolo[4,5-e]azepines and 4,6-dihydro-1H-benzo[5,6]oxepino[3,4-d][1,2,3]triazoles, is reported. The method is versatile, high yielding,and even suitable for domino and one-pot sequential protocols,combining the copper-catalyzed reaction of alkynes and organicazides (CuAAC) with palladium-catalyzed C─H bond activation.A plausible reaction mechanism is proposed.