 23_OTf with an activation barrier of 20.8 kcal/mol. This relatively low free energy of activation is in agreement with the experimental observations and explains why the dearomatization reaction by Bi(4-CO2Etbipy)-HVI occurs at room temperature (Table ). , entries 4 and 5). Furthermore, it was noted that the ortho-quinone product formed by reaction with PhI(O)(OTf)2 decomposed as the reaction time increased (Table , entries 6). This observation suggests that the presence of the Lewis basic bipyridine ligand in Bi(4-CO2Etbipy)-HVI plays an important role in reducing product degradation. Thus, we employed DFT to investigate and understand the underlying reasons for the reactivity differences between PhI(O)(OTf)2 and PhI(O)(OAc)2. For benchmarking purposes, we also studied the oxidation of p-nitrophenol by PhI(O)(TFA)2 computationally to predict the reactivity of this oxidant. As discussed in the previous section, the first redox process is the rate-determining step of the oxidative dearomatization. Consequently, for these three systems we limited our calculations to studying this part of the reaction mechanism. As shown in Figure , the dearomatization commences with the ligand exchange between ArOH and PhI(O)(X)2 (X = OTf, TFA, OAc) via the CIA mechanism, 7 followed by a hypervalent twist and then the redox process via the nucleophilic attack of the ortho-carbon of the phenolate to the oxo ligand.