A reusable polymer-supported copper(I) catalyst for triazole click reaction on water: An experimental and computational study: Polymer-supported Copper(I) Catalyst for Triazole Click Reaction

In the search for establishing a clickable copper-catalysed (3 + 2) Huisgen azide-alkyne cycloaddition (CuAAC) reaction under strict conditions, in particular in terms of preventing the presence of copper particles/traces in reaction products and using an environmentally benign medium such as water, we describe here the synthesis of an aminomethyl polystyrene-supported copper(I) catalyst (Cu(I)-AMPS) and its characterization by means of Fourier transform infrared and energy-dispersive X-ray spectroscopies and scanning electron microscopy. Cu(I)-AMPS was found to be highly active in the CuAAC reaction of various organic azides with alkynes affording the corresponding 1,4-disubstituted 1,2,3-triazoles in a regioselective manner in air at room temperature and using water as solvent. The insolubility and/or partial solubility of the organic azide and alkyne precursors as well as the heterogeneous Cu(I)-AMPS catalytic system points to the occurrence of the cycloaddition at the organic-water interface 'on water' affording quantitative yields of waterinsoluble 1,2,3-triazoles. A mechanistic study was performed using density functional theory aiming at explaining the observed reactivity and selectivity of the Cu (I)-AMPS catalyst in CuAAC reactions.