Efficient synthesis of unsymmetrical 1,4-disubstituted-2,3-diketopiperazines via tandem reductive amination–cyclization

Herein we report the efficient syntheses of 1,4-disubstituted-2,3-diketopiperazines and 1,4,5-trisubstituted-2,3-diketopiperazines, which feature a tandem reductive amination and acylation. Aliphatic and aromatic primary amines serve as viable nucleophiles under the mild reaction conditions.