A magnetically separable palladium catalyst containing a bulky N-heterocyclic carbene ligand for the Suzuki–Miyaura reaction. Issue 1 (30th September 2014)

• Record Type: Journal Article
• Authors: Wang, Z.; Yu, Y.; Zhang, Y. X.; Li, S. Z.; Qian, H.; Lin, Z. Y.
• Is Part Of: Green chemistry. Volume 17:Issue 1(2015)
• Page Start: 413
• Page End: 420
• Publication Date: 2014-09-30
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/c4gc00574k
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : Bulky NHC ligands were employed for preparing magnetic palladium catalysts, which showed excellent activity, stability and reusability towards the Suzuki–Miyaura reaction. Abstract : This work describes the preparation and characterization of a magnetic palladium catalyst with bulky N-heterocyclic carbene (NHC) ligands for the Suzuki–Miyaura cross-coupling reaction. After the 1-(2, 6-diisopropylphenyl)-1 H -imidazole (1-arylimidazole) was modified on the surface of magnetic polymer carriers, palladium diacetate was employed to synthesize the Pd-NHC complex, affording a palladium loading of 0.23 mmol g −1 . This magnetic catalyst showed high catalytic activity towards the Suzuki–Miyaura reaction of phenylboronic acids with aryl bromides in the ethanol–water solution (TON > 87 000). After 21 cycling runs, its catalytic activity decreased slightly, and no leaking of palladium was found either in products or in reaction residue. When other sources of palladium (PdCl2 and 3-Cl-pyridinyl) were employed to synthesize the palladium complex, the stability of the magnetic catalyst was greatly improved to perform the catalysis of Suzuki–Miyaura reactions with aryl chlorides at 100 °C.