The results showed that the [3,3]-sigmatropic rearrangement to the formation of an allenyl azide occurs through a transition structure TS1-2x. The prototropic reactions take place through stepwise mechanisms, involving the abstraction of a proton by a nucleophile (TS11-3X) and the proton transfer from the solvent to the negatively charged allene moiety (TS21-3X) to form the corresponding allenyl azide. To accurately describe the role of methoxide as a nucleophile, four explicit methanol molecules were used in the calculations.