Abstract Simple and efficient Ga (OTf) 3-catalyzed [4+ 3] cycloaddition of 1, 3- diarylpropynones and o-phenylenediamines is developed for the preparation of 2, 4- disubstituted-3H-benzo [b][1, 4] diazepines. The reaction has advantages of using a green solvent, generating a minimal amount of waste, and easy catalyst recycle.
