Covalently immobilized tris(triazolyl)methanol–Cu(i) complexes: highly active and recyclable catalysts for CuAAC reactions

Abstract

Tris(1-benzyl-1H-1,2,3-triazol-4-yl)methanol (3), a highly efficient ligand for CuAAC reactions, has been immobilized onto Merrifield resins through different strategies. The S_N2-supported Cu complex (8) is stable in water and under air; it is active at low catalyst loadings (1 mol%) and at low concentration (down to 0.125 M) in both aqueous and purely organic media. Resin 8 can be repeatedly reused in 1 : 1 MeOH–water for short reaction times (4 h) with the only precaution of Cu(I) reloading every five cycles.