Facile synthesis of achiral and chiral PCN pincer palladium(II) complexes and their application in the Suzuki and copper-free Sonogashira cross-coupling reactions

• Published in: Journal of organometallic chemistry Vol. 694; no. 16; pp. 2555 - 2561
• Main Authors: Zhang, Ben-Shang, Wang, Chao, Gong, Jun-Fang, Song, Mao-Ping
• Format: Journal Article
• Language: English
• Published: LAUSANNE Elsevier B.V 15.07.2009; Elsevier
• Subjects: Aldimine; Chemistry; Chemistry, Inorganic & Nuclear; Chemistry, Organic; Chiral; PCN pincer palladium(II) complexes; Phosphinite; Physical Sciences; Science & Technology; Sonogashira reaction; Suzuki reaction; Sonogashira reaction; Chiral; PCN pincer palladium(II) complexes; Phosphinite; Aldimine; Suzuki reaction; PALLADACYCLES; CRYSTAL-STRUCTURES; CYCLOPALLADATED FERROCENYLIMINE COMPLEXES; LIGAND INTRODUCTION ROUTE; PLATINUM COMPLEXES; HIGHLY EFFICIENT; ARYL BORONIC ACIDS; CATALYTIC-PROPERTIES; CHLORIDES; HECK REACTION
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/j.jorganchem.2009.04.002

Five non-symmetrical PCN pincer palladium(II) complexes 2a– e have been easily prepared in only two steps from readily available m-hydroxybenzaldehyde and characterized. The molecular structures of 2a and 2b were described. The complexes were found to be effective catalysts for the Suzuki and copper-free Sonogashira cross-coupling reactions. Five non-symmetrical PCN pincer palladium(II) complexes [PdCl{C 6H 3-2-(CH NR)-6-( OPR 2 ′ )}] (R = m-ClC 6H 4, R′ = Ph ( 2a); R = Ph, R′ = Ph ( 2b); R = i-Pr, R′ = Ph ( 2c); R = m-ClC 6H 4, R′ = i-Pr ( 2d); R = ( S) -1-phenylethyl, R′ = Ph ( 2e)) have been easily prepared in only two steps from readily available m-hydroxybenzaldehyde and characterized by HRMS, 1H NMR, 13C NMR, 31P NMR and IR spectra. The molecular structures of 2a and 2b have been further determined by X-ray single-crystal diffraction. The obtained Pd complexes were found to be effective catalysts for the Suzuki and copper-free Sonogashira cross-coupling reactions which could be carried out in the undried solvent under air.