C,O-Chelated BINOL/Gold(III) Complexes: Synthesis and Catalysis with Tunable Product Profiles

摘要

Unprecedented stable BINOL/gold(III) complexes, adopting a novel C, O-chelation mode, were synthesized by a modular approach through combination of 1,1'-binaphthalene-2,2'-diols (BINOLs) and cyclometalated gold(III) dichloride complexes ((CN)-N-boolean AND)AuCl2. X-ray crystallographic analysis revealed that the bidentate BINOL ligands tautomerized and bonded to the AuIII atom through C, O-chelation to form a five-membered ring instead of the conventional O, O'-chelation giving a seven-membered ring. These gold(III) complexes catalyzed acetalization/cycloisomerization and carboalkoxylation of ortho-alkynylbenzaldehydes with trialkyl orthoformates.