In recent years, gold-catalysed organic transformations have become important tools to build up molecular diversity. Most of the reported reactions deal with cycloisomerisations or the activation of alkynes and allenes towards nucleophilic attack and, in contrast, there are only a few examples of gold-catalysed homogeneous oxidations.
A. Stephen K. Hashmi from the University of Heidelberg, Germany, and Helmut Bertagnolli from the University of Stuttgart, Germany, et al. describe gold complexes that were prepared and investigated as catalysts for the oxidative esterification of aldehydes. Stabilization by pyridine ligands gave good conversions and the in situ extended X-ray absorption fine structure (EXAFS) study of the reactions indicated that the reaction mixtures contained only mononuclear gold species.
Thus, this is the first proof for a homogeneous gold-catalysed oxidation reaction; the presence of nanoparticles could be excluded experimentally.
- Gold Catalysis: In Situ EXAFS Study of Homogeneous Oxidative Esterification
A. S. K. Hashmi, C. Lothschütz, M. Ackermann, R. Doepp, S. Anantharaman, B. Marchetti, H. Bertagnolli, F. Rominger,
Chem. Eur. J. 2010, 16 (27).