Laboratory of Applied Bioorganic Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
Graduate School of Environmental and Life Science, Okayama University, Okayama, Japan.
Biosci Biotechnol Biochem. 2021 Jan 7;85(1):134-142. doi: 10.1093/bbb/zbaa002.
Synthesis of assumed natural (12R,13S)-enantiomers of pyriculariol (1) and dihydropyriculariol (2), phytotoxins isolated from rice blast disease fungus, Pyricularia oryzae, was achieved using Wittig reaction or microwave-assisted Stille coupling reaction as the key step. The synthesis revealed that the natural 1 and 2 are racemates. Foliar application test on a rice leaf indicated that both the salicylaldehyde core and side chain were necessary for phytotoxic activity. The fungus is found to produce optically active phytotoxins when incubated with rotary shaker, but racemic ones when cultured using an aerated jar fermenter.
从稻瘟病菌（Pyricularia oryzae）中分离得到的植保素吡利枯醇（1）和二氢吡利枯醇（2）被认为是天然存在的（12R，13S）-对映异构体，本文采用Wittig 反应或微波辅助 Stille 偶联反应作为关键步骤，实现了这两种化合物的全合成。该合成揭示了天然 1 和 2 均为外消旋体。在水稻叶片上的叶面喷施试验表明，水杨醛核心和侧链都是产生植保活性所必需的。研究发现，当用旋转摇床培养时，真菌会产生光学活性的植保素，但当使用通气搅拌发酵罐培养时，则会产生外消旋植保素。
