Volatiles from the tropical ascomycete <i>Daldinia clavata</i> (Hypoxylaceae, Xylariales)
作者:Tao Wang、Kathrin I Mohr、Marc Stadler、Jeroen S Dickschat
DOI:10.3762/bjoc.14.9
日期:——
apparatus and analysed by GC-MS. A few compounds were readily identified by comparison of measured to library mass spectra and of retention indices to published data, while for other compounds a synthesis of references was required. For one of the main compounds, 5-hydroxy-4,6-dimethyloctan-3-one, the relative and absolute configuration was determined by synthesis of all eight stereoisomers and gas chromatographic
A Unified Approach for the Stereoselective Total Synthesis of Pyridone Alkaloids and Their Neuritogenic Activity
作者:Henning Jacob Jessen、Andreas Schumacher、Travis Shaw、Andreas Pfaltz、Karl Gademann
DOI:10.1002/anie.201007671
日期:2011.4.26
neurite outgrowth might constitute a valuable approach for the non‐invasive medical treatment of neurodegenerative diseases. With the aid of a bifunctional building block, the total syntheses of a group of pyridone polyenes originally produced by entomopathogenic fungi was achieved (see picture). All of these natural products displayed neuritogenicactivity in the PC‐12 cell line.
Stereoselective Synthesis and Absolute Configuration Determination of Xylariolide A
作者:José Manuel Botubol、Antonio J. Macías-Sánchez、Isidro G. Collado、Rosario Hernández-Galán
DOI:10.1002/ejoc.201201526
日期:2013.4
asymmetric synthesis of the antibacterial and antitumoral natural compound xylariolide A (1) and five stereoisomers has been achieved. The strategy is based on the one-pot epoxidation/lactonisation or dihydroxylation/lactonisation of the hypothetical biosynthetic intermediate xylarioic A acid (8). The absoluteconfiguration of xylariolide A was thus determined to be 3R,4S,5R,1′R,2′R after the synthesis of
抗菌和抗肿瘤的天然化合物木香内酯 A (1) 和五种立体异构体的不对称合成已经实现。该策略基于假设的生物合成中间体木霉酸 (8) 的一锅环氧化/内酯化或二羟基化/内酯化。因此,在合成 1 个差向异构体,即 1'-epi-xylariolide A (3) 和 2'-epi 后,木香内酯 A 的绝对构型确定为 3R,4S,5R,1'R,2'R -xylariolide A (4) 和另外三种非对映异构体 5–7。
The MIDA touch: A concise and highly convergent protecting‐group‐free totalsynthesis of (−)‐myxalamide A involves a stereoselective vinylogous Mukaiyama aldol reaction of a vinylketene silyl N,O‐acetal, together with a one‐pot Stille/Suzuki–Miyaura cross‐coupling reaction using Burke's N‐methyliminodiacetic acid (MIDA) boronate to connect left‐ and right‐hand fragments of the molecule (see scheme)
Asymmetric total synthesis of an acetate analogue of the endophytic unstable secondary metabolite bipolamide A has been achieved for the first time adopting a convergent approach. The key feature of this synthesis includes Evans's asymmetric ethylation, Wittig olefination, Takai olefination, stereoselective Grignard addition and intermolecular Heck coupling. This eventually developed a synthetic route
首次采用收敛方法实现了内生不稳定次级代谢物 bipolamide A 的乙酸酯类似物的不对称全合成。该合成的关键特征包括 Evans 的不对称乙基化、Wittig 烯化、Takai 烯化、立体选择性格氏加成和分子间 Heck 偶联。这最终开发了一种很少发现的带有 acyloin 部分的支化胺的合成路线。我们的合成最终明确地建立了天然存在的不稳定双酚酰胺 A 的未指定 C-8 中心的立体化学。