Reusable ammonium salt-tagged NHC-Cu(I) complexes: preparation and catalytic application in the three component click reaction

A series of ammonium salt-tagged SIPr–Cu(I) complexes have been conveniently synthesized and characterized by NMR and HRMS. They are highly active toward the three component click reaction of benzyl bromide, NaN3 and alkyne with water as solvent at rt. Current water soluble NHC–Cu(I) catalyst could be efficiently used at least four times with an 84% isolated yield of the desired triazole in the last run.