An efficient protocol for the CuAAC reaction catalyzed by metallic copper wire for the synthesis of 1,4-disubstituted triazoles has been developed in supercritical carbon dioxide (scCO2) at 50 °C. The protocol could afford the corresponding products in excellent yields with a very easy work-up procedure. The metallic copper wire could be reused for more than 200 runs without decreasing the catalytic efficiency.

A combination of carboxymethylpullulan (CMP) and Cu2O has been developed as a highly efficient catalytic system for the Huisgen-click reaction. Our results indicate that the acidic CMP could be used for 6 cycles without decreasing the activating efficiency for Cu2O.

An efficient protocol for Huisgen-click reaction catalyzed by Cu(OAc)2·H2O for the synthesis of 1,4-disubstituted triazoles has been developed in supercritical carbon dioxide (scCO2) in the absence of ligand at 36 °C. The protocol could afford the corresponding products in excellent yield at very low catalyst loadings (0.01 mol %).

A combination of Cu(OAc)2·H2O and NH2NH2·H2O, which in situ generates Cu2O-NPs and HOAc in water at room temperature, has been developed as a highly efficient catalytic system for Huisgen click reactions. Our results indicate that the in situ generated Cu2O-NPs and HOAc play important roles in the Huisgen click reaction.

A thermally promoted and CuSO4-catalyzed new version of the Huisgen-click reaction is presented in this Letter. Notably, this protocol was suitable not only for the reactions between organic azides and alkynes, but also for one-pot three-component reactions among alkyl halides, NaN3, and alkynes.