Asymmetric Ring-OpeningTransformation of RacemicAziridines: Enantioselective Route to Benzodiazepines

We report an example of dynamic kinetic resolution (DKR) in general and dynamic kinetic asymmetric transformation (DyKAT) in particular in the ring-opening transformation of racemic 2-aryl-<i>N</i>-tosylaziridines employing a strategically designed <i>N</i>-nucleophile and Cu(I)-(<i>S</i>)-BINAP as the chiral Lewis acid catalyst, furnishing the desired ring-opening products with excellent yield (up to 98%) and excellent enantioselectivity (up to 99% <i>ee</i>). The ring-opening products on intramolecular cyclization using AgNO₃/DBU produced various 1,4-benzodiazepine derivatives in excellent yields (up to 88%) and enantioselectivity (up to 97% <i>ee</i>).