cycloaddition reaction was developed for the expedient synthesis of pharmacologically interesting 3-aryl substituted isoxazolines and isoxazoles through C[double bond, length as m-dash]C bond cleavage. Copper nitrate is employed as a reaction promoter and precursor of nitrile oxides. The given approach features a new mode of cycloaddition from olefinic azlactones, copper nitrate and unsaturated compounds