Triostin A, a cyclic octadepsipeptide, was synthesized with Z–D-Ser [Boc–Ala–MeCys (Bzl)– MeVal]–OH and Z–D-Ser [H–Ala–MeCy (Bzl)–MeVal]–OTce as key intermediates. The synthetic antibiotic was compared with natural triostin A in terms of chromatographic behaviors, NMR spectra, and antimicrobial activity to establish their identity. The NMR data on S, S′-dibenzyldihydrotriostin A showed that this intermediate lacking the disulfide ...