[4+3] Annulation Reactions Of Aza-ortho-quinone Methide

Seven membered N-heterocycles are important motifs in many natural and bioactive compounds,that possess a broad spectrum of applications as pharmaceutical and agrochemical products,and functional materials.Therefore,it is highly desirable to develop mild and straightforward protocols for their synthesis.Based on the highly reactivity of in situ formed aza-ortho-quinone methides,two kinds of seven membered N-heterocycles were obtained with high efficiency.1.An unprecedented protocol for the synthesis of benzotriazepines,which involves tandem reaction of of N-(ortho-chloromethyl)aryl amides and hydrazonoyl chlorides,has been developed.This reaction proceeds through a tandem intermolecular nucleophilic substitution,elimination,intramolecular cyclization and aromatization,leading to a diverse set of benzotriazepines derivatives in moderate to excellent yields.2.A mild and efficient method for the synthesis of benzooxadiazepine derivatives through the base mediated [4+3] cycloaddition of nitrones with N-(ortho-chloromethyl)aryl amides,has been established.This protocol features mild conditions,high efficiency,and wide substrate scopes.