therefore propose it to be the resting state of the catalytic cycle. For the reaction to proceed, one of the phenolate ligands must dissociate from zinc in exchange for CSA to coordinate, leading to complex B; hence the half-order dependence on [phenol] and first-order dependence on [CSA]. Complexation of the Brønsted acid to zinc effectively enhances its acidity, enabling it to activate alcohol 2 towards Friedel-Crafts alkylation, potentially via transition state D. This SN2-type pathway would be favored in the relatively non-polar PhCl solvent; however, we are unable to rule out the SN1-like pathway where ionization occurs with loss of water. Release of product in the presence of excess phenolic substrate turns over the zinc catalyst.