3-(Triflyloxy)benzynes Enable the Regiocontrolled Cycloaddition of Cyclic Ureas to Synthesize 1,4-Benzodiazepine Derivatives

A versatile synthesis of 1,4- benzodiazepinederivatives through the reaction of various 3-(trifluoromethanesulfonyloxy)benzynes with N -( p -toluenesulfonyl) imidazolidin-2-ones is reported. This reaction system provides a 1,4- benzodiazepinebearing a trifluoromethanesulfonyloxy group as a single regioisomer among the four possible regioisomers.