Synthetis studies on biologically active unsaturated lactones of microbial origin.

1.内酯类化合物的合成：内酯类化合物是一系列由粗皮内酯属植物产生的具有生物活性的内酯类化合物。本论文的主要研究内容如下：1.以2-甲基环丙酮为原料，经脱胶-9-内酯(杂环花内酯)反应合成了派瑞内酯B，并建立了新的合成路线。Asperlin及相关天然产物的合成。(1)(-)-月桂内酯的合成：自然界中存在许多具有生物活性的6-取代5，6-二氢-5-羟基(或酰氧基)-2H-吡喃-2-酮。为了建立一条具有光学活性的吡喃酮类化合物的合成路线，以3-三乙基硅氧基-1-丙炔和2，3-O-环己亚甲基-D-甘油醛衍生的(S)-1-甲基-2-氧乙基苯甲酸酯为原料合成了最简单的天然类似物(-)-月桂内酯。(2)合成了天然的(+)-月桂内酯及其异构体。(E，S)-2-苯甲氧基-3-戊烯醛与1-甲氧基-3-三乙基硅氧基-1-丙炔反应。经保护、脱保护、部分氢化、氧化内酯、脱保护等步骤，得到(+)-苯丙内酯及其非对映异构体。(3)(+)-阿司匹林及其异构体的合成：(+)-阿司匹林的乙酰化，氧化得到(+)-阿斯培林和(1‘R，2’S)-异构体。

1. Syntheses of pyrenolides: Pyrenolides are a series of biologically active decanolides produced by Pyrenophora teres. We synthesized pyrenolide B from 2-methylcyclononanone via decan-9-olide (phoracantholide) and established a new synthetic route to decanolide skeleton.2. Syntheses of asperlin and related natural products.(1) Synthesis of (-)-osmundalactone: there are many biologically active 6-substituted 5,6-dihydro-5-hydroxy (or acyloxy)-2H-pyran-2-ones in nature. To establish a synthetic route to optically active pyranones, (-)-osmundalactone, the simplest natural analog, was synthesized from 3-triethylsiloxy-1-propyne and (S)-1-methyl-2-oxoethyl benzoate, which was derived from 2,3-O-cyclohexylidene-D-glyceraldehyde.(2) Syntheses of natural (+)-phomalactone and its isomers : Phomalactone, isolated from Nigerospora sp., was firstly synthesized by a similar strategy as above. (E,S)-2-Benzoyloxy-3-pentenal was reacted with 1-lithoi-3-triethyl-siloxy-1-propynr. After several steps including protection, deprotection, partial hydrogenation, oxidative lactonization and deprotection, (+)-phomalactone and its diastereomer were obtained.(3) Synthesis of (+)-asperlin and its isomer : Acetylation of (+)-phomalactone followed by oxidation afforded (+)-asperlin and (1'R,2'S)-isomer.