Segment Solid-Phase Total Synthesis of the Anthelmintic Cyclooctadepsipeptides PF1022A and Emodepside

Cyclodepsipeptides of the enniation, PF1022 and verticilide families represent a diverse class of highly interesting natural products with respect to their manifold biological activities. However, until now, no practicable solid-phase syntheses of these compounds have been accomplished, probably due to the problematic combination of N-methyl amino acids and hydroxycarboxylic acids. We report herein an efficient synthesis of the anthelmintic PF1022A and its commercial analogue emodepside on Kaiser and Wang resins. Our protocol provides the basis for the solid-phase synthesis of cyclodepsipeptide libraries with a high probability of anthelmintic, antibacterial or insecticidal activity.