Magnetically Separable Proline Ligand

Significance

Magnetic nanoparticle-supported proline ligand MNP-2 was prepared from azide-functionalized magnetite MNP-1 with tert-butyl-N-Boc-4-propargyloxyprolinate through the alkyne-azide [2+3]-cycloaddition reaction (eq. 1). The CuI-catalyzed Ullmann-type coupling reactions of aryl/heteroaryl bromides with various N-heterocycles such as imidazole, pyrazole, indole, and benz­imidazole were carried out in the presence of proline-loaded magnetic nanoparticle MNP-2 as a ligand and Cs₂CO₃ as a base to form the corresponding N-aryl products in 30-98% yield.