Origins of unique gold-catalysed chemo- and site-selective C-H functionalization of phenols with diazo compounds

• Published in: Chemical science (Cambridge) Vol. 7; no. 3; pp. 1988 - 1995
• Main Authors: Liu, Yuan, Yu, Zhunzhun, Zhang, John Zenghui, Liu, Lu, Xia, Fei, Zhang, Junliang
• Format: Journal Article
• Language: English
• Published: England 01-03-2016
• Subjects: Carbenes; Gold; Insertion; Ligands; Mathematical analysis; Origins; Phenols; Water chemistry
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c5sc04319k

In past decade, gold revealed more and more unique properties in carbene chemistry. It was disclosed in our recent communication (
2014,
, 6904) that gold carbenes have unprecedented chemo- and site-selectivity and ligand effect toward the functionalization of C-H bonds in phenols. In this full article, we report a comprehensively combined theoretical and experimental study on the mechanism of the insertion of gold carbenes into C-H and O-H bonds in phenol. It significantly revealed that the ligands have an important effect on C-H insertion and the reaction proceeds through a pathway involving the formation of an enolate-like intermediate. Moreover, two water molecules serving as a proton shuttle are believed to be the key issue for achieving chemoselective C-H functionalization, which is strongly supported by the DFT calculations and control experiments. It is the first time that a clear explanation is given about the prominent catalysis of gold carbenes toward C-H functionalization based on a theoretical and experimental study.