Facile synthesis of 1,4-benzodiazepin-3-ones from o-bromobenzylamines and amino acids via a cascade coupling/condensation process

CuI-catalyzed coupling of 2-bromobenzylamines and α-amino acids and subsequent condensative cyclization (directly or mediated with DPPA) provides 1,4-benzodiazepin-3-ones in moderate yields. Using l-proline and l-valine as the starting materials enantiopure products are obtained although partial racemization occurs for other amino acids.