Scandium(III) triflate as an efficient and reusable catalyst for synthesis of 1,5-benzodiazepine derivatives

2,3-Dihydro-1H-1,5-benzodiazepines have been synthesized in solvent-free conditions in excellent yield from o-phenylenediamines and ketones in the presence of a catalytic amount of Sc(OTf)3. This method is a very easy, rapid, and high yielding reaction for the synthesis of 1,5-benzodiazepine derivatives.