The powerful effect of N-aryl substitution in promoting the thermal rearrangement of 5-spirocyclopropaneisoxazolidines

Article abstract of DOI:10.1016/S0040-4039(99)01339-8

N-Alkyl 5-spirocyclopropaneisoxazolidines rearrange to tetrahydropyridone derivatives by heating. The presence of a phenyl ring on the nitrogen atom significantly reduces the rearrangement temperature. This effect is enhanced by electron-donating substituents and reduced by electron- withdrawing substituents on the phenyl ring.