Comprehensive Study of Okaspirodiol: Characterization, Total Synthesis, and Biosynthesis of a New Metabolite from <i>Streptomyces</i>
作者:Tobias Bender、Tim Schuhmann、Jörg Magull、Stephanie Grond、Paultheo von Zezschwitz
DOI:10.1021/jo060149e
日期:2006.9.1
5]acetal okaspirodiol (4) was isolated from Streptomyces sp. Gö TS 19 as a secondary metabolite in yields up to 380 mg/L. The structure of this cryptic ketotetrol was elucidated by different methods including X-ray analysis, and its equilibration under mildly acidic conditions furnishing three additional isomers was thoroughly studied. Although metabolite 4 is not the thermodynamically favored isomer
从链霉菌(Speptomyces sp。)中分离到新的螺[4.5]缩醛okaspirodiol(4)。GöTS 19作为次生代谢产物,产量高达380 mg / L。通过包括X射线分析在内的不同方法阐明了这种隐蔽的酮咯醇的结构,并对其在弱酸性条件下的平衡状态(提供了另外三种异构体)进行了深入研究。尽管代谢物4不是热力学上受欢迎的异构体,但在平衡条件下仍完成了高产量的全合成,包括立体选择性螺缩醛化。这种方法得益于分子内氢键对螺[4.5]缩醛部分稳定的重要影响。4的生物合成通过对13种C标记前体的进料实验进行了研究,证明了其源于一种新型的稀有混合乙酸酯-甘油生物合成途径。在自然界中螺缩醛的结构多样性及其化学性质的基础上讨论了所有结果。