Propargyl carboxylates react with 1,3-dicarbonyl compounds and electron-rich arenes in the presence of Au(I) catalysts to give enol carboxylates via alpha,beta-unsaturated Au(I) carbenes or Au(I)-coordinated allenes formed by 1,2- or 1,3-acyl migration, respectively.
![Gold-catalyzed addition of carbon nucleophiles to propargyl carboxylates](https://www.iciq.org/wp-content/uploads/2014/03/Gold-catalyzed-addition_eng_noticies_articles_2007_74.gif)