Recent Developments in N2-Selective Functionalizations of 1,2,3-Triazoles

Abstract The widespread use of 1,2,3-triazole compounds in drugs has resulted in a great interest in the efficient synthesis of N2-substituted 1,2,3-triazoles via post triazole functionalization methods. At present, there are many methods for the synthesis of N1-substituted 1,2,3-triazole compounds, but the development of convenient methods for the N2-selective functionalization of 1,2,3-triazoles remains challenging. In general, the greater stability of the N1 tautomer makes the N2 position a non-preferable reactive site, which has limited the application of 1,2,3-triazoles. In this review, we summarized advances in the direct N2-selective functionalization of 1,2,3-triazoles since 2008. 1 Introduction 2 N2-Alkylation 3 N2-Allylation 4 N2-Propargylation 5 N2-Alkenylation 6 N2-Alkynylation 7 N2-Arylation 8 Conclusions and Outlook