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Highly selective synthetic organic reactions utilizing cleavage of C-Cl bond

利用 C-Cl 键断裂的高选择性合成有机反应

基本信息

批准号：
20550036
负责人：
NISHII Yoshinori
金额：
$ 3.08万
依托单位：
Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2010
项目状态：
已结题

项目摘要

1) We developed a stereoselective synthesis of cyclopropane derivatives utilizing a highly stereoselective SMI_2-promoted Reformatsky-type reaction and acylation of 1-chlorocyclopropanecarboxylic esters. The present method is a new avenue for the stereoselective synthesis of highly substituted cyclopropylcarbonyl compounds. Utilizing radical formylation and the present protocols, we achieved a highly stereoselective double-carbon elongation on the dichloro- carbon of gem-dichlorocyclopropanes. We also developed a stereoselective synthesis of cyclopropane derivatives utilizing a highly stereoselective SmI_2-promoted C-silylation and alkylation of 1-chlorocyclopropane- carboxylic esters. Based on the fact that no O-TMS-product was obatained, a SmI_2-O-enolate might not be generated or should exist as a particular intermediate that can not react with TMSCl on oxygen atom. 2) We developed a novel synthesis of 1-aryl-1,2-dihydronaphthalene-3-carboxylic acid esters utilizing a Lewis acid-mediated regioselective ring-expansion of methyl (aryl-hydroxymethyl)cyclopropanecarboxylate. Application of the present method to a total synthesis of natural product is now being performed. 3) We achieved the first total synthesis of a novel (±)-6'-methoxyretrojusticidin B, which was proposed as procumphthalide A, utilizing regiocontrolled benzannulation of an aryl(aryl')-2,2-dichlorocyclopropylmethanol as the key step. 1H-NMR spectral data suggested that the structure of the synthesized product, 6'-methoxyretrojusticidin B, was inconsistent with that of natural procumphthalide A. The revised structural elucidation of natural procumphthalide A was concluded to be 5'-methoxyretrochinensin.

1)我们开发了一种利用SMI_2促进的高立体选择性的Reformsky反应和1-氯丙烷羧酸酯的酰化反应合成环丙烷衍生物的立体选择性方法。该方法为高取代环丙基酮类化合物的立体选择性合成开辟了一条新途径。利用自由基甲酰化和本方法，我们实现了GEM-二氯环丙烷二氯碳的高度立体选择性的双碳延伸。我们还开发了一种利用高立体选择性的SnI_2促进的1-氯环丙烷-羧酸酯的C-硅基化和烷基化反应合成环丙烷衍生物的立体选择性方法。根据没有得到O-TMS-产物的事实，SMI_2-O-烯醇酸可能不会生成或应该作为一种特定的中间体存在，它不能与氧原子上的TMSCl反应。2)利用Lewis酸介导的区域选择性扩环反应合成了1-芳基-1，2-二氢-3-萘甲酸甲酯。现在正在将本方法应用于天然产物的全合成。3)以芳基(芳基‘)-2，2-二氯环丙基甲醇的区域控制苯环化反应为关键步骤，首次实现了新的(±)-6’-甲氧基反式阿司匹林B的全合成。~1H-核磁共振波谱数据表明合成的产物6‘-甲氧基反式青蒿素B的结构与天然原胡萝卜素A的结构不一致，修正后的结构确定为5’-甲氧基反式青蒿素。