Development of Novel Synthetic Reaction Using Cycloalkanones

以1，3-环戊二酮为原料，经多步合成了具有官能化α侧链的PGB_1类似物。通过稳定碳负离子的取代反应，将α-和ω-侧链引入到PGB_1环戊烯酮内酯中。ESR研究证实了稳定碳负离子的取代反应按S1型自由基链机理进行<RN>。对由此获得的PGB_1进行生物活性筛选试验。在本研究合成的PGB_1中，有6个样品对蜱类和水稻害虫有杀虫活性。从S_<RN>1型反应的角度出发，发现在反应过程中形成了稳定的自由基中间体，从而确定了含四元不对称碳原子的环化氮氧自由基的一般制备方法，并对含四元不对称碳原子的2，6-通过环己酮和醛的直接缩合反应，实现了难以用常规方法制备的二烷基酚由二茂锆络合物催化。所得酚类化合物的抗氧化性能与市售酚类化合物的抗氧化性能进行了比较，其抗氧化性能与常用的酚类抗氧化剂体系相当或优于后者。该方法已推广到由酮、醛和酯经季先科反应合成环戊烯酮。

PGB_1 analogues with functionalized alpha-side chain have been synthesized in several steps from 1,3-cyclopentanedion. Introduction of alpha-and omega-side chains into the PGB_1 cyclopentenone skeltone has been accomplished by replacement reaction via stabilized carbanions. The substitution reaction with stabilized carbanion has been confirmed to process via a radical chain mechanism of S_<RN>1 type by the ESR studies. The PGB_1 thus obtained were subjected to the screening test for the biological activities. Among the PGB_1 synthesized in the present study, it was found that 6 samples of these act as insecticide of tick and rice insect. From the consideration of S_<RN>1 type reaction, it was found that a stable radical intermediate is formed in the course of this reaction.By using this methodology, we are able to confirm a general preparation method of cyclized nitroxy radicals bearing quarternary asymmetric carbon.On the other hand, the synthesis of 2,6-dialkylphenols which is difficult to prepare by conventional method is accomplished from the direct condensation reaction between cyclohexanone and aldehydes catalyzed by zirconocene complexes. The anti-oxidant property of the resulting phenols was compared with those of commercial avairable ones, and these were comparable or superier to comventinal phenol system of anti-oxidants. This method has been extended to the cyclopentenone synthesis from ketones and aldehydes, and esters by Tishchenko rection.