A concise and simple click reaction catalyzed by immobilized Cu(I) in an ionic liquid leading to the synthesis of β-hydroxy triazoles
作者:Nasseb Singh
DOI:10.1016/j.crci.2015.07.006
日期:2015.12
Résumé This study describes an ecocompatible, concise, and practically reliable approach for the regioselective synthesis of β-hydroxy triazoles via Huisgen's click coupling reaction among varied epoxides, NaN3, and suitable acetylenes catalysed by immobilized Cu(I) in ionic liquid (IL). This one-pot, atom-economic, efficient, and highly regioselective green protocol ensures higher yield of β-hydroxy triazole scaffolds (85–95%). To make the process ecofriendly, this study emphasizes on the catalyst immobilization technique along with its possible recycling that gave a high reaction yield in up to three runs. The structures of all synthesized compounds have been characterized by comparing 1H nuclear magnetic resonance (NMR), 13C NMR, and mass spectroscopic data with those reported in the literature.
Copper nanoparticles on activated carbon have been found to effectively catalyze the multicomponent synthesis of beta-hydroxy-1,2,3-triazoles from a variety of epoxides and alkynes in water. The catalyst is easy to prepare, reusable at a low copper loading (0.5 mol %), and exhibits higher catalytic activity than some commercially available copper sources. The regio- and stereochemistiy of the reaction has been revised and unequivocally established on the basis of X-ray crystallographic analyses. An NMR experiment has been implemented for the rapid and unmistakable determination of the regiochemistry of the process. Some mechanistic aspects of the reaction have been also undertaken which unveil the participation of copper(I) acetylides.
μ-Hydroxyl trinuclear copper(ii) clusters: reactivity and unusual formation in the three-component synthesis of 1,2,3-triazoles in aqueous media
copper(II) complexes (Cu-1 and Cu-5), we found that the μ-OH trinuclear copper(II) complex (Cu-6) was the active catalyst precursor. Through analysing the reaction intermediates we found that Cu(II) was partially reduced to Cu(I) and an adduct formed during catalytic process, which involves the alkyne coordinating to the Cu centers. This is the first example where a μ-OH trinuclear copper(II) complex has