Transition-metal-catalyzed or metal-free azide–alkyne cycloadditions are methods to access 1,4- or 1,5-disubstituted 1,2,3-triazoles. Although the copper-catalyzed cycloaddition to access 1,4-disubstituted products has been applied to biomolecular reaction systems, the azide–alkyne cycloaddition to access the complementary 1,5 …