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 [(C^N)AuCl ]. X-ray crystallographic analysis revealed that the bidentate BINOL ligands tautomerized and bonded to the Au 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.
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http://dx.doi.org/10.1002/anie.201612243 | DOI Listing |
Chem Sci
September 2024
State Key Laboratory of Chemical Biology and Drug Discovery, Research Institute for Future Food, Department of Food Science and Nutrition, The Hong Kong Polytechnic University Hung Hom Hong Kong China
A novel approach for efficient synthesis of chiral C,O-chelated BINOL/gold(iii) complexes by diastereomeric resolution using enantiopure BINOL as a chiral resolving agent was demonstrated. The BINOL/gold(iii) diastereomers with different solubility were separated by simple filtration, providing optically pure BINOL/gold(iii) complexes with up to >99 : 1 dr. By combining this with an efficient BINOL ligand dissociation process, a simple and column-free method for chiral resolution of racemic gold(iii) dichloride complexes on a gram scale was established, affording their enantiopure forms in good yields.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2018
Laboratoire Hétérochimie Fondamentale et Appliquée, Université Paul Sabatier/CNRS UMR 5069, 118 Route de Narbonne, 31062, Toulouse Cedex 09, France.
Square way to heaven: As a result of their square-planar geometry, the reactive site of gold(III) complexes is much closer to the ancillary ligands. This offers new perspectives in asymmetric catalysis, as recently evidenced by the groups of Wong and Toste with well-defined chiral complexes.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
March 2017
State Key Laboratory of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.
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 [(C^N)AuCl ]. X-ray crystallographic analysis revealed that the bidentate BINOL ligands tautomerized and bonded to the Au 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.
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