Totalsynthese und biologische Evaluierung von Miuraenamiden

Synthesis and biological evaluation of moiramide B derivatives

Moiramide B is a peptide-polyketide hybrid with a bacterial origin and interesting antibiotic activity. Besides its structurally conserved peptide part, it contains a highly variable fatty acid side chain. We modified this part of the molecule by introducing a terminal alkyne, and we then subjected it to click reactions and Sonogashira couplings. This provided a library of moiramide B derivatives with high and selective in vivo activities against S. aureus.

Synthesis and Late-Stage Modification of (-)-Doliculide Derivatives Using Matteson's Homologation Approach

(-)-Doliculide, a marine cyclodepsipeptide derived from the Japanese sea hare, Dolabella auricularia, exhibits potent cytotoxic properties, sparking interest in the field of synthetic chemistry. It is comprised of a peptide segment and a polyketide moiety, rendering it amenable to Matteson's homologation methodology. This technique facilitates the diversification of the distinctive polyketide side chain, thereby permitting the introduction of functional groups in late stages for modifications of the derived compounds and studies on structure-activity relationships.

A Straightforward Synthesis of Polyketides via Ester Dienolate Matteson Homologation

Application of ester dienolates as nucleophiles in Matteson homologations allows for the stereoselective synthesis of highly substituted α,β-unsaturated δ-hydroxy carboxyl acids, structural motifs widespread found in polyketide natural products. The protocol is rather flexible and permits the introduction of substituents and functionalities also at those positions which are not accessible by the commonly used aldol reaction. Therefore, this ester dienolate Matteson approach is an interesting alternative to the "classical" polyketide syntheses.

Total Synthesis of Keramamides A and L from a Common Precursor by Late-Stage Indole Synthesis and Configurational Revision

The marine natural products keramamide A and L, members of the class of anabaenopeptin-type peptides, were synthesized for the first time by a convergent and flexible route. The installation of the substituted tryptophan moieties was accomplished at the very end of the synthesis on the cyclic peptides, and thus enabled the synthesis of both natural products from one common precursor. The preparation of several epimers clearly indicates that the originally proposed relative configurations of both Keramamides A and L were not correct.

Matteson Homologation-Based Total Synthesis of Lagunamide A

Matteson homologation was found to be an excellent tool for the synthesis of the polyketide fragment of lagunamide A. Starting from a chiral boronic ester, a central building block containing all stereogenic centers of the polyketide chain was synthesized via six iterative Matteson homologation steps.

Total synthesis of the natural HDAC inhibitor Cyl-1

A chelate enolate Claisen rearrangement was used as a key step in the first total synthesis of Cyl-1, a cyclic tetrapeptide from Cylindrocladium scoparium.

Total synthesis of desoxycyclomarin C and the cyclomarazines A and B

Removing the β-hydroxy group from the prenylated tryptophan moiety of cyclomarins simplifies the synthesis of these interesting natural products significantly, without having a noteworthy effect on the anti-tuberculosis activity of the cyclomarins.

Synthesis of fully protected, reverse N-prenylated (2S,3R)-3-hydroxytryptophan, a unique building block of the cyclomarins

The rather exotic amino acid of the cyclomarins, is obtained in enantio- and diastereomerically pure and fully protected form.