Totalsynthese der Keramamide A und L aus einer gemeinsamen Vorstufe durch späte Indolsynthese und Revision ihrer Konfiguration

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.

Three Methods for the Solution Phase Synthesis of Cyclic Peptides

Cyclic peptides, which often exhibit interesting biological properties, can be obtained by macrolactamization of adequately protected linear peptide chains. Because of the remarkable biological properties, methods for the efficient cyclization of peptides are of high interest. We herein describe three different protocols for the cyclization of peptides and depsipeptides via amide bond formation. These methods can, in principal, be applied to any linear peptide chain.

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.