Utilization of Fukuyama’s sulfonamide protecting group for the synthesis of N-substituted α-amino acids and derivatives

A novel and general route for the solid phase synthesis of N-substituted α-amino acids has been developed. This synthesis employs Fukuyamaʹs 2-nitrobenzenesulfonamide protecting group for preparation of secondary amines. The versatility of this methodology is demonstrated by the facile synthesis of a trisubstituted diketopiperazine (DKP) skeleton.