Copper catalysis in the synthesis of 1,2,3-triazoles and tetrazoles

Five-membered heterocyclic rings have historically played a role of paramount importance in organic chemistry and in the development of new technologies from this science. These scaffolds have applications in several areas, including medicinal chemistry, agrochemistry, materials science, and catalysis, among others. Particularly, 1,2,3-triazoles have attracted significant attention during the last few years. The chemistry of 1,4-disubstituted 1,2,3-triazole compounds has been widely explored and countless applications and biological activities have been described for these substances. However, the investigation of other regioisomers is fundamental to expand the chemical space occupied by this heterocyclic system, contributing to the development of a new generation of 1,2,3-triazole compounds. In this context, the present review covers the last contributions presented in the literature regarding copper catalysis in the synthesis of 1,2,3-triazoles and tetrazoles, focusing on the synthesis of N2-substituted derivatives.