• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Catalytic, enantioselective bifunctional [4+2]-inverse electron demand hetero-Diels-Alder reactions of chiral ketene enolates and o-Benzoquinone derivatives.
【24h】

Catalytic, enantioselective bifunctional [4+2]-inverse electron demand hetero-Diels-Alder reactions of chiral ketene enolates and o-Benzoquinone derivatives.

机译：手性烯酮烯酸酯和邻苯醌衍生物的催化对映选择性双官能[4 + 2]逆电子需求异Diels-Alder反应。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

This work revolves around the use of ketenes and their catalyst-derived enolates in the synthesis of a variety of synthetically useful and/or biologically active compounds. These reactive intermediates are formed via a unique, catalyst-driven, shuttle deprotonation system. [4+2] cycloaddition reactions between ketene enolates and o-benzoquinone derivatives will be examined. For example, the resulting cycloadducts from o-quinones and ketene enolates are readily converted to alpha-hydroxy esters through a simple, two-step ring opening and deprotection that can be conveniently performed in one pot. o-Benzoquinone imides are used as surrogates to form virtually enantiomerically pure alpha-amino acids and their derivatives. o-Quinone diimides form quinoxalinones in >99% ee, which are useful for drug development because of their structural relationship to benzodiazepines. This methodology is further developed through mechanistic studies and the introduction of a bifunctional catalyst system employing an achiral Lewis acid cocatalyst.;As a complement and a logical follow-up to our lab's previous work on cis-beta-lactams, the synthesis of trans-beta-lactams is then explored. A novel, anionic charged catalyst is examined for its utility in the diastereoselective synthesis trans-beta-lactams.;Despite their discovery over a century ago, ketenes remain interesting and challenging substrates to work with. In particular, monosubstituted ketenes are known to be excellent synthetic intermediates, although their instability can limit its uses. This dissertation focuses on the novel utilization of these flexible and potent compounds generated in situ through our shuttle deprotonation methodology.
机译：这项工作围绕着在合成各种有用的和/或具有生物活性的化合物中使用烯酮及其催化剂衍生的烯酸酯。这些反应性中间体是通过独特的催化剂驱动的穿梭去质子化系统形成的。烯酮烯酸酯和邻苯醌衍生物之间的[4 + 2]环加成反应将被研究。例如，由邻醌和烯酮烯酸酯得到的环加合物易于通过简单的两步开环和脱保护反应容易地转化为α-羟基酯，该反应可在一锅中方便地进行。邻苯醌醌酰亚胺用作替代物以形成实际上对映体纯的α-氨基酸及其衍生物。邻奎宁二酰亚胺以> 99％ee的形式形成喹喔啉酮，由于其与苯并二氮杂structural的结构关系，可用于药物开发。通过机理研究和引入使用非手性路易斯酸助催化剂的双功能催化剂体系，进一步开发了该方法。作为对我们实验室先前在顺式-β-内酰胺上的研究（反式-合成）的补充和合理的后续行动然后探索β-内酰胺。研究了一种新型的阴离子带电催化剂在非对映选择性合成反式β-内酰胺中的效用。尽管乙烯酮在一个多世纪前就被发现，但它们仍是有趣且具有挑战性的底物。特别地，已知单取代的烯酮是优异的合成中间体，尽管它们的不稳定性会限制其用途。本文重点研究了通过我们的航天飞机去质子化方法原位生成的这些灵活有效的化合物的新用途。

著录项

  • 作者

    Abraham, Ciby Joseph.;

  • 作者单位

    The Johns Hopkins University.;

  • 授予单位 The Johns Hopkins University.;
  • 学科 Chemistry Organic.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 181 p.
  • 总页数 181
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 有机化学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号