A simple route to tetrahydro-1,4-benzodiazepin-3-ones bearing diverse N1, N4, and C10 functionalization

We describe an efficient synthesis of enantiopure tetrahydro-1,4-benzodiazepine-3-ones derived from l-alanine. Diverse substitution at N1, N4, and C10 can be achieved by coupling various N-alkyl derivatives of l-alanine and N-allyl-(2-fluoro-5-nitro)benzylamine. Cyclization of this intermediate proceeds in high yield and without racemization, providing diversity at N1. The NO2 group was easily transformed into other functional groups or removed, providing diversity at C10. Finally, oxidative deallylation allows diverse substitution to be installed at N4.