Table 2 Energetics of the reaction with N,C,C-trisubstituted nitrones with aryl methylidenecyclopropane-1,1-dicarboxylates
| Substituents | Activation energy (kcal/mol) | Reaction energy (kcal/mol) | ||
|---|---|---|---|---|
| 4-isomer | 5-isomer | 4-isomer | 5-isomer | |
| R3=–H, R4=–H | +28.9 | +16.6 | −10.3 | −20.9 |
| R3=–OCH3, R4=–CH3 | +29.7 | +17.6 | −10.0 | −20.4 |
| R3=–H, R4=–Cl | +29.1 | +16.2 | −10.4 | −22.0 |