A new simplified protocol for copper(I) alkyne–azide cycloaddition reactions using low substoichiometric amounts of copper(II) precatalysts in methanol

Copper(II) carboxylates are reduced efficiently by methanol in the presence of alkynes and form yellow alkynylcopper(I) polymeric precatalysts that are involved with azides, in the absence of added ligands, in the catalytic cycles that result in the formation of 1,4-disubstituted 1,2,3-triazoles.