A total synthesis of an antifungal cyclic depsipeptide aureobasidin A was first achieved mainly using PyBroP1) as a coupling reagent. The synthetic cyclized product was completely identical with the natural antibiotic in all respects. Some unexpected reactions due to N-methylamino acid were also described.
The first totalsynthesis of antifungal cyclic depsipeptide aureobasidin A is described. The synthesis was achieved mainly using bromotris(pyrrolidino)phosphonium hexafluorophosphate (PyBroP) as a coupling reagent. Peptide cyclization was carried out between L-allo-isoleucine (L-alle1) and L- Pro9 residues in the linear nonapeptide at the final step of the synthesis. Synthesized aureobasidin A was