Asymmetric Ring-Opening Transformation of Racemic Aziridines: 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-N-tosylaziridines employing a strategically designed N-nucleophile and Cu(I)-(S)-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% ee). 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% ee).