• 主题
高级搜索  >
历史搜索 清空历史
首页> 美国卫生研究院文献>other >Broadly Applicable Stereoselective Syntheses of Serrulatane Amphilectane Diterpenes and Their Diastereoisomeric Congeners using Asymmetric Hydrovinylation for Absolute Stereochemical Control
【2h】

Broadly Applicable Stereoselective Syntheses of Serrulatane Amphilectane Diterpenes and Their Diastereoisomeric Congeners using Asymmetric Hydrovinylation for Absolute Stereochemical Control

机译：广泛使用的立体异构合成SerrulataneAmphilectane二萜及其非对映异构体的立体选择性合成用于绝对立体化学控制

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务，本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文，但由于OA文献来源多样且变更频繁，仍可能出现获取不到、文献不完整或与标题不符等情况，如果获取不到我们将提供退款服务。请知悉。
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A stereogenic center, placed at an exocyclic location next to a chiral carbon in a ring to which it is attached, is a ubiquitous structural motif seen in many bioactive natural products including di- and tri-terpenes and steroids. Installation of these centers has been a long-standing problem in organic chemistry. Few classes of compounds illustrate this problem better than serrulatanes and amphilectanes, which carry multiple methyl-bearing exocyclic chiral centers. Nickel-catalyzed asymmetric hydrovinylation (HV) of vinylarenes and 1,3-dienes such as 1-vinylcycloalkenes provide an exceptionally facile way of introducing these chiral centers. This manuscript documents our efforts to demonstrate the generality of the asymmetric HV to access not only the natural products, but also their various diastereoisomeric derivatives. Key to success here is the availability of highly tunable phosphoramidite Ni(II)-complexes useful for overcoming the inherent selectivity of the chiral intermediates. The yields for HV reactions are excellent, and selectivities are in the range of 92–99% for the desired isomers. Discovery of novel, configurationally fluxional, yet sterically less demanding, 2,2′-biphenol-derived phosphoramidite Ni-complexes (fully characterized by X-ray) turned out to be critical for success in several HV reactions. We also report, a less spectacular, yet equally important role of solvents in a metal-ammonia reduction for the installation of a key benzylic chiral center. Starting with simple oxygenated styrene derivatives we iteratively install the various exocyclic chiral centers present in typical serrulatane [e.g., a (+)-p-benzoquinone natural product, elisabethadione, nor-elisabethadione, helioporin D, a known advanced intermediate for the synthesis of colombiasin and elisapterosin] and amphilectane [e.g., A–F, G–J and K,L- pseudopterosins] derivatives. Our attempts to synthesize a hither-to elusive target, elisabethin A, led to a stereoselective, biomimetic route to pseudopterosin A–F aglycone.
机译：立体形成中心位于与其连接的环中手性碳旁边的外环位置，是在许多生物活性天然产物（包括二萜和三萜和类固醇）中普遍存在的结构基序。这些中心的安装一直是有机化学领域的长期难题。很少有化合物能比带有多个带有甲基的环外手性中心的六氟烷和两性烷更好地说明这个问题。乙烯基芳烃和1,3-二烯（例如1-乙烯基环烯烃）的镍催化不对称氢乙烯基化（HV）提供了引入这些手性中心的异常简便的方法。该手稿记录了我们为证明不对称HV不仅可获取天然产物，而且还可获取其各种非对映异构衍生物的通用性而做出的努力。成功的关键在于可获得高度可调节的亚磷酰胺Ni（II）-络合物，可用于克服手性中间体的固有选择性。 HV反应的收率非常好，所需异构体的选择性在92–99％的范围内。发现新颖的，形态上可变的，但在空间上要求不高的2,2'-双酚衍生的亚磷酰胺Ni-络合物（完全由X射线表征）对于成功完成多个HV反应至关重要。我们还报告说，在关键的苄基手性中心的安装过程中，溶剂在减少金属氨气中的作用不那么引人注目，但同样重要。从简单的氧化苯乙烯衍生物开始，我们迭代地安装典型的serrulatane中存在的各种环外手性中心[例如，（+）-对苯醌天然产物，伊利沙伯二酮，去甲利沙伯乙二酮，Helioporin D，一种已知的用于合成哥伦比亚的先进中间体和elisapterosin]和amphilectane [例如，A–F，G–J和K，L-伪蝶呤]衍生物。我们合成迄今难以捉摸的靶标伊丽莎白A的尝试导致了立体选择性仿生途径生成拟蝶呤AF糖苷配基。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
代理获取

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