Highly N2-selective arylation of 4,5-unsubstituted and 4-substituted 1,2,3-triazoles was achieved for the first time by the Pd/1 catalyst system. A wide range of N2-aryl-1,2,3-triazoles were prepared from aryl bromides, chlorides, and triflates with excellent N2 selectivity. Density functional theory calculations suggest that the formation of N2-arylated 1,2,3-triazoles is favored kinetically.
“Highly N2-selective palladium-catalyzed arylation of 1,2,3-triazoles”, Angew. Chem. Int. Ed., 2011, 50(38), 8944-7.