Design and applications of an efficient amphiphilic “Click” CuI catalyst in water
Résumé
The copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) using the conventional Sharpless–Fokin catalyst that consists of CuSO4 + Na ascorbate, the most well-known and used “click” reaction, is considerably accelerated by the addition of a tris(triazolyl)-poly(ethylene glycol) (tris-trz-PEG) amphiphilic ligand in water under ambient conditions. Only parts per million amount of CuI were necessary to reach quantitative yields with TONs up to 86000 and TOFs of 3600 h–1. The ligand was fully recycled, and the catalyst was reused at least six times without decomposition. Large-scale syntheses were also successfully achieved with 93% yield. The catalyst was applied to the efficient synthesis of various useful functional products with medicinal, catalytic, targeting, and labeling properties.