Cuprous oxide on charcoal-catalyzed ligand-free synthesis of 1,4-disubstituted 1,2,3-triazoles via click chemistry

Cuprous oxide on charcoal (Cu2O/C), the preparation of which is described for the first time, catalyzes the formation of 1,4-disubstituted 1,2,3-triazoles from organic azides and terminal alkynes in good to excellent yields (69-94%). These disubstituted triazoles can be equally efficiently generated in a one-pot process from alkyl bromides, sodium azide, and terminal acetylenes in 50% aqueous isopropanol containing a suspension of the catalyst. This obviates the necessity to isolate potentially explosive organic azides.