A one carbon staple for orthogonal copper-catalyzed azide–alkyne cycloadditions

Abstract

We describe herein the use of α-hydroxy-β-azidotetrazoles, easily prepared in one step from α,β-epoxynitriles, as new scaffolds for orthogonal CuAAC reactions performed on the same carbon atom. After a first ligation involving an alkyne with the β-azido moiety, treatment with EDC smoothly releases an alkyne from the remaining α-hydroxytetrazole, ready for a second CuAAC reaction. This “double click” process can be performed iteratively, leading to triazolamers.