TBHP/CoCl2‐Mediated Intramolec­ular Oxidative Cyclization of N‐(2‐Formylphenyl)amides: An Approach to the Construction of 4H‐3,1‐Benz­oxazin‐4‐ones

Abstract

AbstractThe intramolecular oxidative cyclization of N‐(2‐formylphenyl)amides has been realized through an oxidative C(sp2)–O(sp2) bond‐forming reaction between an aldehyde carbon and amide oxygen. This new strategy, which uses tert‐butyl hydroperoxide (TBHP) as an oxidant and CoCl2 as the catalyst, allows for the efficient Co‐catalyzed synthesis of useful benzoxazin‐4‐one derivatives and features readily available starting materials and mild reaction conditions.