Reaction of Huisgen zwitterion with 1,2-benzoquinones and isatins: Expeditious synthesis of dihydro-1,2,3-benzoxadiazoles and spirooxadiazolines

Abstract

The zwitterionic intermediate generated from dialkyl azodicarboxylate and triphenylphosphine on reaction with 3-methoxy-1,2-benzoquinones afforded dihydro-1,2,3-benzoxadiazoles. N-Substituted isatins furnished spirooxadiazolines under similar conditions.