Efficient synthesis of substituted piperazinones via tandem reductive amination–cyclization

A new strategy for the preparation of substituted piperazinones features a tandem reductive coupling and SN2-cyclization of a 2-chloro-N-(2-oxoalkyl)acetamide (1) and a primary amine (2). The method is convenient for diversity-oriented synthesis, since a wide variety of amines may be used in the ring-forming reaction to produce N-substituted piperazinones (3).