DFT/B3LYP theoretical study has been performed in order to interpret the kinetic-thermodynamic competition between compounds obtained by reaction of the methoxide ion on the 7-methyl 4-nitro benzofuroxan. Geometry, atomic charge distribution, transition states, IRC path, thermodynamic, and kinetic parameters ([Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]*, [Formula: see text]*, and [Formula: see text]*) have been calculated for all possible products. In gaseous state or in the presence of water as solvent, all [Formula: see text] values were found to be negative, ranging from [Formula: see text]12.54[Formula: see text]kcal mol[Formula: see text] to [Formula: see text]29.85[Formula: see text]kcal mol[Formula: see text] in water, indicating that all possible products should form spontaneously. Those values indicated the possible observation of all products but experimenters only detect simultaneously two [Formula: see text]-complexes in C5 and C7 among three possibilities. The Fukui indices obtained by NBO atomic charge distribution confirm the super electrophilicity of those two sites. For transition states barriers, [Formula: see text]* ranged from 18.98[Formula: see text]kcal mol[Formula: see text] to 42.12[Formula: see text]kcal mol[Formula: see text] in gaseous state and from 18.59[Formula: see text]kcal mol[Formula: see text] to 24.22[Formula: see text]kcal mol[Formula: see text] in water. The unexpected result of our calculations is that the most stable compound is the unobserved carbanion but it also exhibits the highest activation barrier. Our results indicated the existence of two consecutive kinetic/thermodynamic competitions that occur in separate periods. The simultaneous observation of the three compounds is impossible because compound 4 occurs as a trace at the time compound 2 disappears completely. Experimental reinvestigation of the studied reaction leads by a very slow process to the earlier unobserved carbanion. Reaction mechanisms were also discussed on the basis of IRC calculations.

Reaction of the methoxide ion on the 7-methyl 4,6-dinitrobenzofuroxan (DNBF) 1 has been studied theoretically by means of DFT/B3LYP technique in order to interpret the kineticthermodynamic competition between the three possible compounds that are carbanion DNBF -4 and two complexed forms (2, 3) of the methoxide group in positions 5 and 7 respectively. Optimized Geometry, nbo atomic charge distribution, thermodynamic/kinetic parameters (∆ r H°T, ∆ r S°T , ∆ r G°T, ∆H*, ∆S* and ∆G*) and IRC path have been calculated for possible products and their transitional states using water as solvent. All obtained ∆ r G°T are negative, ranging from -19.16 to -42.87 kcal mol -1 , indicating the possible observation of all products but the experimenters only detected the anionic form DNBF -. Fukui indices, which were calculated by means of NBO atomic charge distribution, confirm the electrophilicity of the sites C5 and C7. Transition states barriers, ΔG* are 14.97 , 15.16 and 21.94 kcal mol -1 for the three possible products 2, 3 and 4 respectively in water. As expected, the most stable compound is the carbanion but it exhibits also the highest activation barrier. If this situation engenders formally a double kinetic-thermodynamic competition, the very weak activation energy of the two complexes in C5 and C7 makes improbable the simultaneous detection of the three expected compounds.

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