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首页> 外文学位 >Synthetic approaches to the total synthesis of agelastatin A and intramolecular Diels-Alder reactions of 4-vinylimidazole derivatives.
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Synthetic approaches to the total synthesis of agelastatin A and intramolecular Diels-Alder reactions of 4-vinylimidazole derivatives.

机译：全合成法拉汀A的合成方法和4-乙烯基咪唑衍生物的分子内Diels-Alder反应。

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摘要

The work presented in this dissertation focuses on the development of new methods for the elaboration of simple imidazoles into complex molecules and is divided into two parts. The first part describes the development of ring closing metathesis (RCM) as a means to prepare bicyclic imidazoles. It was initially planned to apply this reaction in an approach to the oroidin-derived marine alkaloid agelastatin A. A number of RCM precursors were synthesized and evaluated in the RCM reaction either using the first or second generation Grubbs' catalysts. Unfortunately, none of the attempts to construct the 5-5 fused bicyclic system turned out to be successful except for substrates which possessed an allyl group at N1 and a vinyl group at C5. Attempts to transform the imidazole ring of a number of these substrates into an imidazolone also failed. It was found that, by using the second generation Grubbs' catalyst, and protonating N3, the RCM reaction works well for forming 5–6 fused bicyclic compounds in high yields and low catalyst loadings (5 mol%). This is the first demonstration that RCM reactions can be applied to imidazole-containing substrates. This method could be utilized to synthesize a number of imidazole-containing polycyclic compounds and natural products.; The second part of this dissertation describes the intramolecular Diels-Alder reactions of 4-vinylimidazole derivatives. This research seeks to develop the intramolecular Diels-Alder reaction of 4-vinylimidazole derivatives as a means to construct polycyclic compounds and for application in an approach to the total synthesis of ageliferin and congeners. Initial investigations have centered on investigation of the influence of protecting groups (such as trityl, benzyl and N-dimethylsulfamoyl) on the imidazole N1 position and on the dienophile structure. The synthesis and Diels-Alder reactions of a number of imidazole-based trienes from urocanic acid are described. To date only acetylenic dienophiles and precursors containing amino linkers participate successfully in the intramolecular Diels-Alder reaction. This may in part be due to the bulky nature of the protecting group. Future investigations of the 5-vinylimidazole derivatives may address this issue and the work to synthesize the 5-vinylimidazole D-A precursors has been initialized. An efficient method to prepare amino-containing D-A precursors has been developed.
机译：本文的工作主要集中在将简单的咪唑加工成复杂分子的新方法的研究上，该研究分为两个部分。第一部分描述了闭环复分解（RCM）作为制备双环咪唑的一种手段的发展。最初计划将该反应以一种方法应用到得自麦冬蛋白的海洋生物碱阿司他汀A中。使用第一代或第二代Grubbs催化剂在RCM反应中合成并评估了许多RCM前体。不幸的是，除了在N1处具有烯丙基且在C5处具有乙烯基的底物之外，构建5-5稠合双环系统的尝试均未成功。将许多这些底物的咪唑环转化成咪唑酮的尝试也失败了。研究发现，通过使用第二代格鲁布斯的催化剂并使N3质子化，RCM反应可很好地形成5-6个稠合双环化合物，且产率高且催化剂用量低（5 mol％）。这是首次证明RCM反应可以应用于含咪唑的底物。该方法可用于合成许多含咪唑的多环化合物和天然产物。本文的第二部分描述了4-乙烯基咪唑衍生物的分子内Diels-Alder反应。这项研究旨在开发4-乙烯基咪唑衍生物的分子内Diels-Alder反应，作为构建多环化合物的一种手段，并用于一种全合成衰老蛋白和同类物的方法中。最初的研究集中在保护基团（例如三苯甲基，苄基和N-二甲基氨磺酰基）对咪唑N1位置和亲双烯体结构的影响上。描述了从尿烷酸的许多咪唑基三烯的合成和Diels-Alder反应。迄今为止，仅炔属二烯亲和物和含有氨基接头的前体成功地参与了分子内Diels-Alder反应。这可能部分是由于保护基团的庞大性质。对5-乙烯基咪唑衍生物的进一步研究可能会解决这个问题，并且已经开始了合成5-乙烯基咪唑D-A前体的工作。已经开发了制备含氨基的D-A前体的有效方法。

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  • 作者

    Chen, Yingzhong.;

  • 作者单位

    The University of Texas at Arlington.;

  • 授予单位 The University of Texas at Arlington.;
  • 学科 Chemistry Organic.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 p.208
  • 总页数 467
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 有机化学;
  • 关键词

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