Study for Highly Stereocontrolled Reactions by Liquid Crystalline Mesophases

液晶中间相高度立体控制反应的研究

基本信息

批准号：
62570944
负责人：
NAGAMATSU Tomohisa
金额：
$ 1.34万
依托单位：
Kumamoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

Photodimerizations and thermal cycloadditions in thermotropic liquid crystalline media were explored in order to show the utility of liquid crystals in organic reaction and chemical significance of the liquid crystalline phases was clarified.1. A well documented photodimerization of uracils seemed to be a suitable reaction for the present study, and provided information regarding highly preferred orientations of solutes in liquid crystalline media. Thus methyluracils were irradiated with a high pressure HG-lamp in isotropic and anisotropic media including frozen solutions. The photodimer distribution and conversion yields were determined as a function of temperature and solvent phase. Smectic liquid crystalline medium significantly enhanced the stereoselectivity and the rate in photodimerization, in strong contrast to the isotropic phase reaction which gave poor dimer-selectivity and yield.2. Alkyl and aryl cholesteryl fumarates were prepared to serve as a liquid crystalline dienophile in Diels-Alder reaction. Some of them showed cholesteric liquid crystial phases in temperature ranges suitable to the cycloaddition. The reaction of n-hexyl cholesteryl cholesteryl fumarate in mesomorphic phase as a dienophile with cyclopentadiene gave the optically active cycloadducts in 10% enantiomeric excess. On the other hand, the reaction of methyl cholesteryl fumarate with 2,6-dimethoxyanthracene gave 2,6-dimethoxy-9,10-dihydro-9,10-ethano-anthracene-11(syn),12(syn)-dicarboxylic acid and the 11(anti),12(anti)-isomer in a ratio of 96 : 4 (92% d.e.). These results clearly showed that a cholesteric mesophase could stereochemically control the diels-Alder reaction to a considerable extend.

探索了热液晶培养基中的光二聚化和热环加成，以表明液晶在有机反应中的实用性和液体晶体相的化学意义。1。尿嘧啶的光二聚化似乎是本研究的合适反应，并提供了有关液晶介质中溶质高度优选方向的信息。因此，在各向同性和各向异性培养基（包括冷冻溶液）中，用高压HG-lamp辐照甲基尿嘧啶。光电二聚体的分布和转化率是根据温度和溶剂相确定的。近晶液晶培养基显着增强了光二聚化的立体选择性和速率，与各向同性相反应形成鲜明对比，这给出了二聚体 - 选择性差和产量的差。2。准备烷基和芳基胆固醇富马酸盐，以作为Diels-Alder反应中的液晶二烯蛋白。其中一些在温度范围内显示出适合环加成的胆汁液体液晶相。 N-己基胆固醇胆固醇在中形相中作为二酚与环戊二烯的反应，在10％的对映体过量的情况下，具有光学活性的环载体。另一方面，富马酸甲甲酯与2,6-二甲基二氨基氨基烯的反应给出了2,6-二甲氧基-9,10-dihydro-9,10-乙二醇-11（syn），12（syn），12（syn） - 二羧酸和11（anti），11（anti），12（anti），12（anti），抗抗）-isomers-isomers-isomers，均为96％。这些结果清楚地表明，胆固性中间体可以立体化学控制Diels-Alder反应以相当大的延伸。