Describes the synthesis of isoxazolines from aryl cyclopropanes when treated with sodium nitrite in trifluoroacetic acid. Observation on alkyl-substituted isoxazole from 2,2-dichlorobicyclo[4.1.0]- heptane; Reaction of benzyl cyclopropanes with the reagent used in synthesis of isoxazolines from acryl cyclopropanes; Expectation on the occurrence of chemical reactions.