in totalsynthesis. We thus describe the synthesis of a putative biomimetic tetracyclic intermediate. The constructive steps are an intramolecular Diels–Alder reaction to install the isoindolone core of cytochalasins, whose branched precursor was obtained from a stereoselective Ireland–Claisenrearrangement performed from a highly unsaturated substrate. This also constitutes a formal synthesis of trichoderone
Aspochalasins 是亮氨酸衍生的细胞松弛素。它们的复杂性与高度的生物合成氧化有关,在此启发了全合成中的两相策略。因此,我们描述了推定的仿生四环中间体的合成。建设性步骤是分子内 Diels-Alder 反应,以安装细胞松弛素的异吲哚酮核心,其分支前体是从高度不饱和底物进行的立体选择性爱尔兰 - 克莱森重排中获得的。这也构成了木霉酮 A 的正式合成。
Consequences of Isostructural Main‐Chain Modifications for the Design of Antimicrobial Foldamers: Helical Mimics of Host‐Defense Peptides Based on a Heterogeneous Amide/Urea Backbone
Fraternal twins: Oligoureas and γ‐peptides are isosteric, quasi‐isostructuralhelicalfoldamers endowed with distinct biomolecular recognition properties. Combination of the two backbones to generate urea/amide hybrids (see picture) was found to give more potent yet less cytotoxic antimicrobialhelicalfoldamers.
peptide–polyketide was isolated from the endophytic fungus Periconia sp. F-31 and bears a unique tricyclic core structure. The key steps are a glycolate aldol reaction and a Diels–Alder reaction utilizing an Evans auxiliary for controlling the stereochemistry. Furthermore, a late-stage equilibration was employed.
Total Synthesis and Absolute Configuration of (−)-Berkeleyamide A
作者:Jonathan Sperry、Eric B. J. Harris、Margaret A. Brimble
DOI:10.1021/ol902525k
日期:2010.2.5
A chiral-pool approach to (−)-berkeleyamide A 1 based on a diastereoselective nitrile oxide [3 + 2]-cycloaddition completes the first total synthesis establishing the absolute stereochemistry of the natural product.
hybrid metabolites, were discovered from the endophytic fungus Periconia sp. F-31. Their structures and absolute configurations were elucidated by extensive spectroscopic data and electronic circular dichroism analyses. Preliminary biological evaluation revealed that pericoannosins C–D exhibited anti-HIV activities with IC50 values of 15.5 and 13.5 μM. Furthermore, the bioinspired syntheses of pericoannosins