Isobutyl Nitrite‐Mediated Synthesis of Quinoxalines through Double C−H Bond Amination of N‐Aryl Enamines.

An efficient and metal‐free double C−H bond amination of N‐aryl enamines using isobutyl nitrite (IBN) has been developed. This method enables the preparation of functionalized quinoxalines in good to excellent yields and tolerates a variety of N‐aryl enamines with diverse functional substituents. Mechanistic studies revealed the presence of a key β‐imino oxime ester intermediate. A quinoxaline derivative could be prepared from β‐carbonyl ester in one‐pot sequence on a gram scale. Finally, two important quinoxaline scaffolds were easily prepared in moderate yields over two steps. [ABSTRACT FROM AUTHOR]