Total Synthesis and Configurational Revision of Mozamide A, a Hydroxy-Brunsvicamide

The marine cyclopeptide mozamide A, a member of the class of anabaenopeptin-type peptides, was synthesized for the first time via a convergent and flexible route. The installation of the substituted tryptophan moieties was accomplished at the very end of the synthesis and thus allows easy modifications at this position. Comparison of the NMR data of the synthesized cyclopeptide with the natural product clearly indicates that the originally proposed structure of mozamide A cannot be correct. The synthesis of two other diastereomers allowed correction of the configuration of three amino acid building blocks. Mozamide A contains l-Val, d-Lys, and l-Ile (instead of d-Val, l-Lys, and l-allo-Ile) and is a hydroxylated brunsvicamide.