Propargylic esters are versatile substrates for Au-based catalysts. However, under typical conditions the starting Au-coordinated propargylic ester 1 is in rapid equilibrium with the gold vinylic carbenoid species 2 and with gold allene species 3. A number of factors dictate which intermediate is lower in energy and which type of products form.
(Hot Paper & Cover)
![Golden carousel in catalysis: The cationic gold/propargylic ester cycle](https://www.iciq.org/wp-content/uploads/2014/03/Golden-carousel-in-catalysis_eng_noticies_articles_2008_10.gif)