According to the literature, the first step of prototropic pathway involves a methoxide as nucleophile, which is susceptible to form hydrogen bonds with methanol molecules of the solvent. Indeed, it was necessary to consider discrete solvent molecules, for obtaining energies consistent with experimental results. For this purpose, we used the supermolecule approach. The optimized TS corresponding to the methoxide attack on the C 1 of CN-substituted propargylic azide (1h) was taken as starting geometry for the search of TS(MeOH)n clusters. Individual methanol molecule was added around the methoxide oxygen in different orientation. Then, the structures so found, were optimized at B3LYP/6-31+G(d,p) level in methanol (SMD). The IRC calculations followed by full geometry optimizations were used to verify the corresponding reactant and product complexes. The differences between the energy barriers of the proton abstraction and the sigmatropic rearrangement for propargylic azides substituted with CN and H (1h and 1b, respectively) were compared with the experimental data. Based on our results, four methanol molecules were necessary to describe the prototropic process adequately. (See the Supporting Information for a more details).