Acid Activation of Organogold Complexes

During the last five years new transformations that require the activation of one, or more, molecules by two gold centres have been developed.  

Overall, the use of well-defined, silver-free catalysts in gold catalysis helps to design more cost-effective protocols and contribute to the overall sustainability of the procedure. To highlight the latter point, in this chapter we will mostly discuss gold-catalysed protocols that do not require silver additives in order to generate active catalysts. 

In this section, we will focus on highly efficient gold-catalysed transformations, i.e. catalyst loadings 0.1 mol%, and will pay special attention to protocols that afford high turnover numbers (TON) and frequencies (TOP). 

1 Highly Efficient Hydration/Hydroalkojg lation Reactions 

Addition of alcohols to unsaturated carbon molecules is one of the most straightforward and environmentally friendly procedures to form C-O bonds. Several species are known to catalyse such transformations. Among them, gold complexes have proven to be extremely active to catalyse the addition of oxygen nucleophiles to all nes, in order to produce the corresponding ketone, ketal or vinylether species. Moreover, such reactions are among the most efficient gold-catalysed transformations reported to date. 

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