Synthesis of Spiroisoxazolines via TEMPO/NaNO2-Catalyzed Aerobic Oxidative Dearomatization.

A catalytic, aerobic oxidative dearomatization protocol has been developed for the preparation of spiroisoxazline scaffolds from oximes using TEMPO and NaNO2 as the catalyst and O2 as the sole oxidant. This dearomatization methodology features its mild reaction conditions, good functional group tolerance, and an unprecedented broad substrate scope, encompassing phenols, aryl ethers, thiophenols, aryl sulfides, etc.