A convenient synthesis of chiral 2-methylenebenzo[e][1,4]diazepin-5-ones via a one-pot reductive cyclodehydration with retention of chirality

Total synthesis of optically pure (+)-Fuligocandin A from L-proline has been achieved in 29% overall yield. The key step, one-pot reductive cyclodehydration of the chiral 2-nitrophenyl-1,3-dicarbonyl compound, proceeds with >98% retention of configuration. This method represents a convenient approach to the synthesis of 2-methylenebenzo[e][1,4]diazepin-5-ones containing one chiral center. A series of benzo[e][1,4]diazepin-5-one derivatives have been successfully synthesized with retention of chirality by the one-pot reaction developed in this work. A possible reductive cyclodehydration mechanism was also proposed.