The Solution Phase Synthesis of Diketopiperazine Libraries via the Ugi Reaction: Novel Application of Armstrong′s Convertible Isonitrile.

Abstract This communication describes the generation of high-yielding solution phase diketopiperazine libraries via a ‘3-step, 1-pot’ procedure, employing the Ugi multi-component reaction (MCR), followed by BOC deprotection and cyclization to diketopiperazine (DKP). Exploitation of Armstrong's convertible isonitrile in the Ugi reaction utilising an ‘internal nucleophile’ approach for diketopiperazine formation is presented.