The molecular mechanism of the decomposition reaction of nitroethyl benzoates catalyzed by Lewis acids based on boron element-BH 3 and BF 3 -was studied using density functional theory methods. These reactions take place much faster than the uncatalyzed process. However, the presence of fluorinated Lewis acids has a unique influence on the molecular mechanism. In the case of BF 3 , a change from a one-step mechanism to a two-step one involving a zwitterionic intermediate is observed.