Progress towards the synthesis of piperazimycin A: synthesis of the non-proteogenic amino acids and elaboration into dipeptides

This Letter describes the synthesis of the five non-proteogenic amino acids required for the total synthesis of piperazimycin A, and synthetic elaboration into multiple dipeptides. Importantly, this Letter details the first example of an elusive piperazic acid–piperazic acid coupling to form this key C5–C14 dipeptide.