Facile Synthesis of Disubstituted Isoxazoles from Homopropargylic Alcohol via CN Bond Formation

A novel iron-catalyzed aerobic oxidative reaction to synthesize disubstituted isoxazoles from homopropargylic alcohol, t-BuONO, and H2O is developed. The method provides mild conditions to afford a variety of useful substituted heterocycles in an efficient and regioselective manner. The mechanism has been studied and proposed, which indicates that the transformation can be realized through construction of a CN bond and CO bond, C–H oxidation, and then cyclization. Moreover, this method can be enlarged to gram scale.