The 1,3-dipolar cycloaddition reaction of C-methylnitrone with nitroethylene was studied using DFT at the B3LYP/6-31G~* level. Self- consistent reaction field (SCRF) method was used to consider the solvent effect of cyclohexane and acetonitrile. In such reaction the reactants have four approaching modes. The structures and frequencies of reactants, intermediates, transition states and products in different circumstances were optimized and calculated. In any circumstances the four reactions are all exothermic reactions with lower energy barriers, so the four products are produced easily. By calculation it is found that in gas phase and cyclohexane solvent, the energy barrier of endo-4 is the lowest one, while in acetonitrile solvent, the energy barrier of endo-5 is the lowest.

Key words: CYCLOADDITION REACTION, SOLVENT EFFECT, NITRONE, SELF-CONSISTENT FIELD, NITRO COMPOUNDS, CYCLOHEXANE, ETHYLENE