Switching the Reaction Mode of 4-Methoxycarbonyl-4-chloro-5-spirocyclopropaneisoxazolidines by N-Aryl Substitution

Abstract

4-Methoxycarbonyl-4-chloro-5-spirocyclopropaneisoxazolidines, easily obtained by in situ cycloadditions of nitrones to methyl 2-chlorocyclopropylideneacetate and 2-chlorospiropentylideneacetate, in contrast to their known thermal rearrangements leading to delta-lactams, undergo rearrangement to their respective tetrahydropyridones, when the nitrone nitrogen is substituted by an aryl moiety.