has specified product has specified reactant azide 1,2,3-triazole acetylenic compound [3+2] cycloaddition 1,3-dipolar cycloaddition alkyne-azide click reaction "click" reaction 'click' reaction A [3+2] cycloaddition reaction between an azide and an alkyne to give a 1,2,3-triazole, needing only heat to proceed. Huisgen cycloaddition Huisgen reaction Huisgen's 1,3-dipolar cycloaddition Note: The term "click reaction" was originally used in a broader sense to refer to any coupling that took place cleanly and quickly in quantitative yield, but it now always seems to be used in this narrower sense. RXNO RXNO:0000269 alkyne-azide Huisgen cycloaddition alkyne-azide Huisgen reaction azide-alkyne Huisgen cycloaddition azide-alkyne Huisgen reaction azide-alkyne click reaction click reaction