Abstrakt
The present "gold-rush" in chemistry started in the nineties with a report of a gold-catalyzed addition of methanol to alkynes, which shook the conception of gold as an inert metal. Here, we present a mechanism of this reaction and demonstrate that actually two gold cations in cooperation activate the C-C triple bond and mediate the methanol addition, which results directly in formation of a diaurated intermediate.
This reaction intermediate was detected by electrospray ionization mass spectrometry, labeling and infrared multiphoton dissociation spectroscopy, which clearly revealed the addition of the methoxy group to the C-C triple bond. The kinetics of the reaction was determined from NMR experiments.
The experimental results are complemented by theoretical calculations, which provide an overall picture of the reaction mechanism.