Synthesis of 2-aminobenzoxazoles and 3-aminobenzoxazines via palladium-catalyzed aerobic oxidation of o-aminophenols with isocyanides.

A Pd-catalyzed aerobic oxidation of o-aminophenols and isocyanides for the synthesis of 2-aminobenzoxazoles and 3-aminobenzoxazines has been achieved in an air atmosphere. The procedure constructs 2-aminobenzoxazoles and 3-aminobenzoxazines with moderate to excellent yields and a broad substrate scope. Apart from experimental simplicity, this methodology has the advantages of mild reaction conditions and easily accessible starting materials. Furthermore, the utility of this method has also been successfully applied to the synthesis of other types of useful nitrogen heterocycles.