Applications of the fluorinated 1,3-dipolar compounds as the building blocks of the heterocycles with fluorine groups. Part XII. Synthesis of trifluoromethylisoxazolines and their rearrangement into trifluoromethylaziridines [1]
-Methyl--trifluoromethylnitrone cycloadded with various alkynes to give 3-trifluoromethyl-4-isoxazolines. The isolated isoxazolines further underwent the valence rearrangement into 2-trifluoromethylaziridines under more drastic conditions. Unusual stability of both trifluoromethylisoxazolines and -aziridines is discussed on the basis of the electronic effect of trifluoromethyl group.