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

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.