1,3‐Dipolar cycloaddition reactions of 2‐phenyl‐4‐arylidene‐5(4<i>H</i>)‐oxazolones with nitrile oxides

Abstract

Abstract Stable nitrile oxides are added stereospecifically and regioselectively to the carboncarbon double bond of 2‐phenyl‐4‐arylidene‐5(4 H )‐oxazolones resulting spiro‐derivatives 3, 5 . The spectral properties of the reaction products are discussed. The cycloadducts give several substituted isoxazolines via an opening of the oxazolone ring with nucleophilic reagents.