Construction of macrocyclic thiodepsipeptides: synthesis of a nosiheptide 'southern hemisphere' model system.

A 20-membered macrocyclic thiodepsipeptide has been synthesized as a model for the southern hemisphere of nosiheptide, the key steps being assembly of an acyclic precursor by amide coupling of indole and thiazole fragments followed by formation of the thiolactone in the macrocyclization step.