Studies on The Synthesis of Sesquiterpenes as Host-specific Phytotoxins Directed towards Novel Insecticides.

寄主特异性真菌对植物产生的植物毒素的研究为阐明其作用方式和开发新的杀虫剂而受到重视。然而，这些致病性毒素的数量不足以进行生物学研究，因为从自然来源获得的毒素并不多。本项目的目标是合成这些致病性倍半萜，为生物学研究提供大量光学纯净的天然同分异构体及其类似物。从面包酵母不对称还原制得e.e为98.4%的羟基酯开始，经过20个步骤，手性合成了孢原- ao 1（13-去氧酚酮），总产率为8.4%。通过建立这一高效的方法，探索了获得这些致病性紫堇倍半萜的一般途径。这样就得到了gigantenone，外接gigantenone，现象酮，相油酮和类似物。利用这些样品，生物学研究正在进行中，初步实验表明，即使是外聚体也具有天然同分异构体60-70%的活性。进一步的研究可能揭示这些倍半萜作为植物病原和真菌产孢物质的生物学意义。

Studies on phytotoxins produced by host-specific fungi againdt plants have been paid much attention to clarify the mode of action as well as to develope new insecticides. The amount of these pathogenic toxins, however, not sufficient for biological study, because they are not much available from natural sources. The target of this project is the synthesis of these pathogenic sesquiterpenes to afford natural isomers and their analogs in optically pure forms in substantial amount for biological study.Starting from the hydroxyester with 98.4% e.e. prepared by the asymmetric reduction with bakers yeast, chiral synthesis of sporogen-AO 1( 13-desoxyphomenone ) was achieved in overall 8.4 % yield through 20 steps. By the establishment of this efficient method, general route to afford these pathogenic eremophilane sesquiterpenes was explored. Thus, gigantenone, epi-gigantenone, phomenone ,phase-olinone and analogs were obtained. Using these samples, biological studies is going on, and preliminary experiment showed that even epimer has 60-70% activity of natural isomers. Further studies may reveal biological meaning of these sesquiterpene as pthogens against plants and as sporogenic substances against fungi.