Evaluation of catalytic activity of copper salts and their removal processes in the three-component coupling reactions

The catalytic activity of a wide range of copper salts, including Cu(l) and Cu(II), has been examined in the Cu-catalyzed three-component coupling reactions of sulfonyl azides, terminal alkynes, and amines, alcohols, or water to afford N-sulfonyl amidines, imidates, and amides, respectively. Furthermore, the investigation on the ligand effect in our protocol has revealed that certain types of ligands such as tris(benzyltriazolylmethyl)amine (TBTA) exhibited notable acceleration effects on the coupling reaction. The facile and efficient methods for removing copper salts from reaction mixture were also examined.