Some Aspects of the Azide-Alkyne 1,3-Dipolar Cycloaddition Reaction

Some peculiar features of two most commonly used catalytic systems (Cul and CuSOVsodium ascorbate) controlling the regioselectivity of 1,3-dipolar cycloaddition of azides to terminal alkynes have been studied. Their potentialities, main disadvantages, and limitations have been demonstrated by a number of examples, including reactions of low-molecular-weight azides and alkynes containing heterocyclic substituents. The possibility of using novel reagents in click reactions is discussed.