Abstract

The chapter is devoted to the recent developments in the synthesis of 1,2,3- triazoles and their selected applications. Since the introduction of a classic Huisgen reaction which involved thermal 1,3-dipolar cycloaddition of alkynes to azides, its catalytic modifications have been elaborated, allowing the regioselective preparation of 1,4- and 1,5-disubstituted derivatives in copper(I)- or ruthenium(II)-catalyzed cyclizations (click reactions). Most of the other synthetic pathways generally also utilize organic azides or sodium azide, although methods based on other starting materials (e.g. hydrazine derivatives) are also of importance. A special attention is paid to the preparation of chiral triazole derivatives. Various applications of triazoles are also discussed, with a focus on their use as isosteres of biological functionalities, sensors for ions and neutral molecules, in catalysis and in construction of supramolecular assemblies.