Copper Immobilized on Nanosilica Triazine Dendrimer (Cu(II)-TD@nSiO2)-Catalyzed Regioselective Synthesis of 1,4-Disubstituted 1,2,3-Triazoles and Bis- and Tris-Triazoles via a One-Pot Multicomponent Click Reaction

An efficient, atom-economical, and regioselective synthesis of a wide range of 1,4-disubstituted 1,2,3-triazoles in excellent yields has been achieved via a one-pot three-component reaction of alkynes and sodium azide with organic halides or α-bromo ketones catalyzed by Cu(II)-TD@nSiO2/sodium ascorbate at room temperature. This catalytic system also showed excellent activity in the synthesis of bis- and tris-1,4-substituted 1,2,3-triazoles. Moreover, the catalyst could be recycled and reused for seven cycles without any loss in its catalytic activity.