Overriding the alkynophilicity of gold: Catalytic pathways from higher energy Au(i)-substrate complexes and reactant deactivation via unproductive complexation in the gold(i)-catalyzed propargyl Claisen rearrangement

Article abstract of DOI:10.1039/c2ob27231h

Computational and experimental analysis of unusual substituent effects in the Au-catalyzed propargyl Claisen rearrangement revealed new features important for the future development of Au(i) catalysis. Despite the higher stability of Au-alkyne complexes, they do not always correspond to the catalytically active compounds. Instead, the product emanates from the higher energy Au(i)-oxygen complex reacting via a low barrier cation-accelerated oxonia Claisen pathway. Additionally, both intra and intermolecular competition from other Lewis bases present in the system, for the Au(i) catalyst, can lead to unproductive stabilization of the substrate/catalyst complex, explaining hitherto unresolved substituent effects.