Total synthesis of an antifungal cyclic depsipeptide aureobasidin A

Article abstract of DOI:10.1016/0040-4020(96)00132-9

The first total synthesis 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-aIle¹) and L-Pro⁹ residues in the linear nonapeptide at the final step of the synthesis. Synthesized aureobasidin A was completely identical with the natural antibiotic with respect to antifungal activity and physicochemical properties. Unusual reactions due to N-methylamino acid, an oxazoline-mediated reaction and an N, O-acyl migration, are also described.