Novel chiral 4,1-benzoxazepine-2,5-diones have been unusually synthesized in a single step by exploiting the chiral pool methodology. Substituted anthranilic acids afford N-acylanthranilic acids and (3R)-3-alkyl-4,1-benzoxazepines-2,5-dione upon coupling with α-chloroacids or α-bromoacids, respectively.