SYNTHESIS OF UNUSUAL BIOLOGICALLY ACTIVE TERPENES

这项研究的主要目标是继续在一个 高级[3，3]Sigmatroy在构造中的应用 结构类型多种多样的复杂萜类。这种方法论 所有迹象表明，这是我们能力上的一个非常重要的进步 简明扼要地获取各种类别的重要天然产品 固执己见的态度。这些新战略是基于进一步的 利用阴离子氧位和Claisen重排反应合成环氧乙烷 由7-10组成的异常中型环系的构造 组成原子。许多被选中的潜在的适用性 针对不同治疗领域的目标使该计划的这一阶段 特别及时，并构成重要的补充理由。 一种利用串联的极短合成法合成Cyathin B3 动力学拆分和氧合化学构筑中心 七元环，以立体控制的方式，具有适当的绝对 我们将检查配置。在同样的时尚中，一条异常短小的 桥头快速施工的脆性内酯的合成 烯烃烯丙基过氧化氢正在计划中。高水平的融合 描述计划中的杏仁酸和紫草酚的精制。这 整个阴离子氧化钴工艺的方面已经严重 在过去的研究中被忽视，值得相当大的开发。这个 复杂的分子可以用这种方法来阐述的速度 技术可能是无与伦比的。 这一策略也将在我们计划的方法中发挥作用 Verecynarmin A.在这种情况下，两个必要的建筑之一 BLOCKS是一种天然存在的呋喃萜类挥发油。在所有的 在推力上方，可制备类似物以提供附加的 深入了解各自协议的灵活性。 扩环克莱森重排预计将促进 几种劳伦辛代谢物的快速构建 异金酸苷，以及龙须草中的草二环二萜类化合物 打字。涉及新的二重Tebbe-Claisen序列的过程是 被开发并推广到合成赛洛司醇I。最后， 两次采用脂环Claisen重排是作为 克隆度胺投射路线中的关键立体化学决定因素。

The primary objective of this research is to continue to develop at an advanced level the utility of [3,3] sigmatropy for the construction of complex terpenes of widely varied structural type. This methodology gives every indication of being a very important advance in our ability to access diverse classes of important natural products in a concise and stereocontrolled manner. These new strategies are based on the further exploitation of the anionic oxy-Cope and Claisen rearrangements for con- struction of unusual medium-sized ring systems consisting of 7-10 constituent atoms. The latent applicability of many of the selected targets to various therapeutic areas make this phase of the program particularly timely and constitutes important added justification. An exceptionally short synthesis of cyathin B3 which exploits tandem kinetic resolution and oxy-Cope chemistry to construct the central seven-membered ring in stereocontrolled fashion with proper absolute configuration will be examined. In like fashion, an exceptionally short synthesis of crispolide that features rapid construction of bridgehead olefinic allylic hydroperoxides is planned. High levels of convergency characterize the planned elaboration of albolic acid and vinigrol. This aspect of the overall anionic oxy-Cope process has been seriously neglected in past studies and warrants considerable exploitation. The rapidity with which complex molecules can be elaborated by this technique is probably unrivaled. This tactic will also see service in our planned approach to verecynarmin A. In this instance, one of the two necessary building blocks is the naturally occurring furanoterpene evodone. In all of the above thrusts, analogues may be prepared in order o provide added insight into the flexibility of the respective protocols. Ring-expanding Claisen rearrangements are expected to facilitate the rapid contruction of several laurencin metabolites such as laurenyne and isolaureatin, as well as oxabicyclic diterpenoids of the eunicellane type. A process involving a novel two-fold Tebbe-Claisen sequence is to be developed and extended to a synthesis of ceroplastol I. Finally, two-fold adoption of the alicyclic Claisen rearrangement is to serve as the key stereochemical determinant in a projected route to cleomdolide.