5,7-membered cyclometallated gold(III) complexes with pyridine-phenyl-oxazoline N^C^N ligands as catalysts for organic transformation reactions under silver-free conditions

Abstract

A series of 5,7-membered cyclometallated gold(III) complexes with N^C^N tridentate ligands are developed as catalysts, which are prepared via transmetalation of pyridine-phenyl-oxazoline ligand-containing organomercury compounds with potassium gold(III) chloride (KAuCl4) with up to 86% yields. Investigation on the synthesis and catalytic activity of the newly developed gold(III) complexes under silver-free conditions results in >90% conversion for propargylamines and up to >99% conversion for bifunctional modification of oligosaccharides via three-component (A3)-coupling reactions. Employment of the tridentate gold(III) complexes also successfully catalyzes the carboalkoxylation reaction of acetal alkynes. These results reveal potential applications of such 5,7-membered tridentate gold(III) complexes as catalysts for organic transformation reactions and modification of biomolecules.