Iron‐ or Zinc‐Mediated Synthetic Approach to Enantiopure Dihydroquinoxalinones

A general and efficient synthesis of enantiopure dihydroquinoxalinones has been developed using naturally occurring amino acids as starting materials. The reductive cyclization of N ‐( o ‐nitroaryl)amino esters was performed by using iron and zinc metal under mild conditions in a water/ethyl acetate mixture. The corresponding dihydroquinoxalinones were obtained in moderate to high yields and high enantiomeric purity, among which 7 new compounds were unprecedented in the literature.