Synthesis of the cyclic nonapeptide of chlorofusin using a convergent [3+3+3]-fragment coupling strategy

A [3+3+3]-fragment coupling strategy was successfully applied in the synthesis of the nonacyclopeptide of chlorofusin, a potent natural antagonist against p53–MDM2 interactions. The accomplished convergent synthesis includes parallel syntheses of three tripeptides and their sequential assembly, and macrocyclization of the linear precursor to the required 27-membered nonacyclopeptide.