LAUSR

The factors responsible for the experimentally observed acceleration of π-acid-catalyzed reactions induced by α-cationic phosphines and group 15 analogues have been computationally explored within the density functional theory framework. To this end, the gold(I)-catalyzed hydroarylation reactions of phenylacetylene and mesitylene involving both neutral and cationic ligands (L) have been quantitatively analyzed in detail using the combination of the activation strain model of reactivity and the energy decomposition analysis methods. It is found that the activating effect of the cationic ligand finds its origin in the much stronger interaction between the deformed reactants along the entire reaction coordinate, which in turn derives from the much higher π(acetylene) → σ*(Au–L) interaction in the initially formed acetylene-gold(I) π-complex.