In Situ Generation of Copper Nanoparticles by Rongalite and Their Use as Catalyst for Click Chemistry in Water

Abstract

Abstract A novel, efficient and green protocol for the copper‐catalyzed azide–alkyne cycloaddition (CuAAC) reaction by using copper nanoparticles (CuNPs), generated in situ by a green reducing agent, rongalite, is reported. Terminal alkynes reacted with benzyl, aryl and alkyl azides in the presence of copper nanoparticles and β ‐cyclodextrin ( β ‐CD) in water. The reactions exclusively generated the corresponding regiospecific 1,4‐disubstituted 1,2,3‐triazoles in good to excellent yields. Notably, in situ generation of copper nanoparticles does not require any additional stabilizing agents or special reaction conditions. β ‐cyclodextrin plays dual role as a stabilizing agent as well as phase transfer catalyst. This protocol is also applicable for gram scale reactions.