New Synthesis of Oxygen Heterocycles

本课题研究了新的含氧杂环化合物的合成方法，并对其具有生物活性进行了研究。第一章介绍了-二氧膦基-丁烯内酯类化合物的合成及其在-内酯类合成中的应用。以-膦丁烯内酯和2-（甲酰基烷基）-1,3-二硫烷的二乙缩醛为原料，简单、高效地合成了环霉素及其类似物。第二章介绍了-亚甲基内酯的新合成方法。以二氧基膦基乙酸和烯丙基溴为原料制备的-二氧基膦基、-不饱和羧酸，易发生碘内酯和硒内酯的内酯化反应，生成-磷内酯和-硒内酯。多聚甲醛与-磷酸内酯的Wittig-Horner反应可产率较高的-亚甲基-内酯。该合成方法已成功地应用于天然化合物frulanolide的合成。第三章介绍了3,4-融合香豆素的新合成方法。邻羟基苯甲醛与-二羟膦基-丁内酯的Witting-Horner反应定量产率为3-（羟乙基）香豆素。经DBU处理后，香豆素容易转化为3-乙烯基香豆素。乙烯基香豆素与各种亲二酚试剂Diels-Alder反应得到功能化的3,4-融合香豆素。

In this project, new synthesis of oxygen heterocycles, which are expected to exhibit biological activities, was studied.In chapter 1, synthesis of -diethoxyphosphinyl- -butenolides and their application to the general synthesis of -lactones with , -fused ring systems were described. Cyclosarkomycin and its analogues were easily and efficiently synthesized in few steps from the -phosphono-butenolide and diethly acetal of 2-(formylalkyl)-1,3-dithianes.In chapter 2, new synthesis of -methylene lactones was described. A various kinds of -diethoxyphosphinyl- , -unsaturated carboxylic acids, which were prepared from diethoxy-phosphinylacetic acid and allylic bromides, easily underwent iodo- and selenolactonization to produce -phosphono-iodo and -selenolactones. The Wittig-Horner reaction of the - phosphonolactones with paraformaldehyde provided -methylene- -lactones in good yields. This synthetic methodology was successfully applied to the synthesis of frullanolide, which is a naturally occurring compound.In chapter 3, new synthesis of 3,4-fused coumarins was described. The Witting-Horner reaction of o-hydroxybenzaldehydes with -diethoxyphosphinyl- -butyro-lactone gave 3-(hydroxyethyl)-coumarins in quantitative yields. The coumarins were easily converted into 3-vinylcoumarins by treatment with DBU. The Diels-Alder reaction of the vinylcoumarins with various dienophiles gave functionalized 3,4-fused coumarins.