Alkyne is an unsaturated hydrocarbon containing at least one carboncarbon triple bond. Featuring a reactive functional group, alkynes participate in many organic reactions. But specially usefull when used as substrate of Strain-promoted azide-alkyne cycloaddition (SPAAC) together with azide substrate when both come close in the active site of an enzyme ( 'click reaction') and in 'Staudinger ligation'. lending to combinatorial chemistry.