The mechanism for the gold-catalyzed aerobic oxidation of alcohols was studied using a series of parasubstituted benzyl alcohols (Hammett methodology). The competition experiments clearly show that the rate-determining step of the reaction involves the generation of a partial positive charge in the benzylic position (i.e. hydride abstraction). This was further substantiated by the determination of a significant kinetic isotope effect (k H / k D = 1.41), when employing an alcohol substrate deuterated in this position.

The gold-catalyzed aerobic oxidation of aldehydes proceeds through development of a partial negative charge and has a significant kinetic isotope effect (kH/kD = 2.8-2.9), which illustrates that activation of the C-H bond takes place in the rate-determining step.