Ozonations of alkoxy- and (acyloxy)-substituted alkylidene-lactams 1 and 5 or of the alkylidene-sultams 9 and 10 proceeded by regioselective cleavage of the exocyclic CC bonds (Schemes 1 and 2). These bonds are part of an enamide system and, therefore, possess considerable polarity as shown by 13C-NMR spectra. As a result, the partly known maleimides 3 and 6 or the ‘sulfonimides’ 11 were obtained.
barrier and reaction free energy, were calculated using density functional theory (DFT), and influencing factors of the reaction were discussed. Theoretical computations showed that this nucleophilicsubstitution is favorable both kinetically and thermodynamically, while electron-withdrawing groups on phenols are harmful to such reactions. This study will provide new knowledge and insights on the chemical