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首页> 外文学位 >Hydroalumination cross coupling chemistry using enynols & uncatalyzed Diels-Alder reactions of siloxacyclopentenes prepared from hydrosilylation of enynols.
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Hydroalumination cross coupling chemistry using enynols & uncatalyzed Diels-Alder reactions of siloxacyclopentenes prepared from hydrosilylation of enynols.

机译：使用烯醇的氢铝化交联化学和由烯醇的硅氢加成反应制备的硅氧烷环戊烯的未催化Diels-Alder反应。

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摘要

For some time the Welker research group has been attaching metals to the third carbon of a diene 0.1 used in Diels-Alder chemistry. The basic structure of a diene is illustrated below in Figure 0.1 (1).*;The purpose behind this metal diene is three fold. First, a large metal helps keep the diene in the reactive s-cis confirmation, a requirement for a Diels-Alder reaction. Second, the presence of a bulky metal can also help control the diene and dienophile from generating the endo Diels-Alder product. The endo product is traditionally the most favored product due to the fact it results from pi bond overlap between the diene and dienophile 0.2. The endo product also results in a syn addition cycloadduct 0.3. By blocking the endo approach using a bulky metal a synthetically viable pathway to the exo product is achieved 0.4, resulting in the anti addition product 0.5 (see Figure 0.2). The traditional diene 0.2 allows the dienophile access to its pi orbitals, resulting in an endo product 0.3. However the diene 0.4 that has a metal attached (if the metal is bulky enough) can block the dienophile resulting in the exo product 0.5. Third, by placing a metal on the diene, one of the terminal carbons (1 or 4) becomes more electronegative than the other thereby helping to direct regiochemistry.*;Initially in the Welker group, this was done by using cobalt on the diene (1). While this method worked well, it only worked in stoichiometric amounts of cobalt and could not be adapted to a catalytic system. This posed a problem due to the high cost of cobalt. To this end a new strategy was designed, in which a diene would have a main group metal on the third carbon. Specifically, a series of dienes, will be made using aluminum and silicon, the 3 rd and 2nd most common elements found in the earth's crust, respectively (2). While aluminum and silicon have been used in organic chemistry for some time their ability to assist cycloaddition chemistry is somewhat limited. To expand the synthetic usefulness of aluminum and silicon dienes a transmetallation reaction will also need to be developed to replace the aluminum or silicon with a synthetically versatile transition metal such as Pd.;*Please refer to dissertation for diagrams.
机译：一段时间以来，Welker研究小组一直将金属与Diels-Alder化学中使用的二烯0.1的第三碳相连。二烯的基本结构如下图0.1（1）所示。*；该金属二烯的作用是三重。首先，大金属有助于将二烯保持在反应性顺式确认中，这是Diels-Alder反应的要求。其次，大块金属的存在还可以帮助控制二烯和亲二烯物产生内Diels-Alder产物。由于二烯与亲二烯体0.2之间的π键重叠，导致内产物传统上是最受欢迎的产品。最终产物还导致顺式加成环加合物0.3。通过使用笨重的金属阻止内切法，可实现通往exo产品的合成可行途径0.4，从而产生抗加成产物0.5（见图0.2）。传统的二烯0.2使亲二烯体能够进入其pi轨道，从而得到内产物0.3。但是，连接有金属的二烯0.4（如果金属足够大）会阻止亲二烯体生成exo产物0.5。第三，通过在二烯上放置一种金属，末端碳原子（1或4）之一比另一个碳负电性更高，从而有助于指导区域化学。*;最初在Welker组中，这是通过在二烯上使用钴完成的（ 1）。虽然此方法效果很好，但仅以化学计量的钴起作用，无法适应催化系统。由于钴的高成本，这带来了问题。为此目的，设计了一种新的策略，其中二烯将在第三碳上具有主族金属。具体来说，将使用铝和硅制成一系列二烯，这分别是地壳中最常见的第三和第二大元素（2）。尽管铝和硅已经在有机化学中使用了一段时间，但它们辅助环加成化学的能力还是受到一定限制。为了扩大铝和硅二烯的合成用途，还需要开发一种金属转移反应，以合成多用途的过渡金属（例如Pd）代替铝或硅。*请参阅相关图表以了解图表。

著录项

  • 作者

    Crook, Kenneth Edward.;

  • 作者单位

    Wake Forest University.;

  • 授予单位 Wake Forest University.;
  • 学科 Chemistry Organic.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 104 p.
  • 总页数 104
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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