International audience1,3-Dipolar cycloadditions of aryl nitrile oxides 2d-f to various racemic 3-hydroxy- and 3-acyloxy-but-1-enes 1a-c proceeded with complete regioselectivity to afford the corresponding 3,5-disubstituted isoxazolines in good yields. The steric and/or electronic effect of an acyloxy group at the allylic position on the stereoselectivity has been studied