LITHIUM PERCHLORATE DIETHYL ETHER MEDIATED REACTIONS

本补助金续期申请的主要重点是进一步探讨 反应性和选择性的一些有机反应，在高度 极性介质如3.0-5.0 M高氯酸锂-乙醚， 应用于生物学感兴趣的分子。 这项建议是 分为三个部分。 本建议的第一部分集中于 离子Diels-Alder反应及其在全合成 endiobic acid A、11-oxosteroids和lycopodine。建议的所有研究 这一领域将具有基本性质，以便界定界限， 这个潜在的有用反应的范围。 第二部分重点论述 阳离子[5+2]环加成反应， 在过去的30年里，尽管它具有潜力， 从事天然和非天然产物合成的人。我们有 发现使用3.0 M的 在三甲基甲硅烷基三氟甲磺酸酯的存在下， 我们建议 研究了一些分子间和分子内阳离子[5+2]环加成反应 反应，以确定我们的调查结果的一般性。我们提出 为了将上述化学方法应用于新的非- 类固醇雌激素，miroestrol。 此外，我们计划准备一个数字， 与紫杉醇相关的双环[5.3.1]系统。 在最后一节，我们 将致力于完成他勃松宁的合成， 一种新的伊博加生物碱的方法。

The major focus of this grant renewal application is to probe further the reactivity and selectivity of a number of organic reactions in highly polar media such as 3.0-5.0 M lithium perchlorate-diethyl ether with applications to molecules of biological interest. This proposal is divided into three parts. The first part of this proposal concentrates on ionic Diels-Alder reactions with applications to the total synthesis of endiandric acid A, 11-oxosteroids, and lycopodine. All studies proposed in this area will be of a fundamental nature in order to define limits and scope of this potentially useful reaction. The second part focuses on cationic [5+2] cycloaddition reactions which have received only scant attention during the past 30 years despite the potential it holds for those engaged in the synthesis of natural and unnatural products. We have found that the yields can be dramatically improved by employing 3.0 M LiClO4-EtOAc in the presence of trimethylsilyl triflate. We propose to examine a number of inter- and intramolecular cationic [5+2] cycloaddition reactions in order to determine the generality of our findings. We propose to apply the above chemistry to the total synthesis of the novel non- steroidal estrogen, miroestrol. In addition we plan to prepare a number of bicyclo [5.3.1] systems related to taxol. In the final section, we will focus on completion of a synthesis of tabersonine and development of a novel approach to iboga alkaloids.