容易的迪尔斯-阿尔德反应与由促进的皮里丁
Peter M Graham1, David A Delafuente, Weijun Liu
1Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA.
Journal of the American Chemical Society
|July 28, 2005
概括
一种新方法使用复合物将简单的二烯转化为有价值的异核二烯. 这种方法使重要制药构建块的立体选择性合成成为可能.
科学领域:
- 有机化学 有机化学
- 药用化学 医学化学
- 催化剂是一种催化剂.
背景情况:
- 异氨基核是生物活性天然产品 (如伊波加和坎塔兰类类化合物) 中的关键结构图案.
- 有效和立体选择性合成路径到功能化异核素对药物开发至关重要.
- 目前用于合成异核胺的方法有限,需要新的策略.
研究的目的:
- 开发一种新的,直接的方法,从易于获得的皮里丁前体中构建异核丁核.
- 在温和条件下实现功能化异核素的立体选择性合成.
- 通过使用性催化剂,使人能够获得富含恩安的异核素.
主要方法:
- 使用pi基复合物通过破坏它们的芳香性来激活化物.
- 采用在激活二烯和缺电子基之间的立体选择性迪尔斯-阿尔德反应.
- 通过将催化剂与性烯 (α-烯) 衍生而成,以诱导反选择性.
主要成果:
- 展示了一种新的方法,可以直接从化物中合成异核胺基架.
- 在温和条件下实现立体选择性迪尔斯-阿尔德反应,产生多种功能化异核素.
- 通过使用从α-pinene衍生出的性 wolsten催化剂,成功生产了以enantio丰富的isoquinuclidines.
结论:
- 这项研究提出了一种从根本上新的异核胺合成方法,克服了以前方法的局限性.
- 开发的方法提供了一条通用而有效的途径,用于药物化学的有价值的异核胺衍生物.
- 使用奇拉烯催化剂为复杂药物中间体的不对称合成开辟了道路.
相关概念视频
![[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12417.jpg&w=3840&q=75)
01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
01:31Diels–Alder vs Retro-Diels–Alder Reaction: Thermodynamic Factors
The Diels–Alder reaction is thermally reversible, meaning that the reaction reverts to the starting diene and dienophile under suitable temperatures. The forward reaction gives a cyclohexene derivative and is favored at low to medium temperatures. The reverse process, also called retro-Diels–Alder reaction, is a ring-opening process favored at high temperatures.
01:28Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
The Diels–Alder reaction is one of the robust methods for synthesizing unsaturated six-membered rings. The reaction involves a concerted cyclic movement of six π electrons: four π electrons from the diene and two π electrons from the dienophile.
01:29Diels–Alder Reaction: Characteristics of Dienes
The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction.
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
01:27Aldol Condensation with β-Diesters: Knoevenagel Condensation
The Knoevenagel condensation is an aldol-type reaction involving the condensation of aldehydes or ketones with active methylene compounds such as β-diesters to produce substituted olefins.
01:24Diels–Alder Reaction: Characteristics of Dienophiles
In a Diels–Alder reaction, the diene is usually an electron-rich system and acts as a nucleophile, whereas the dienophile is electron-deficient and functions as an electrophile. Much like the diene, the nature of the dienophile significantly impacts the outcome of the reaction.
Characteristics of Dienophiles
Generally, the best dienophiles are alkenes containing electron-withdrawing substituents such as carbonyl, nitrile, and nitro groups. The feasibility of a Diels–Alder reaction depends on...
Characteristics of Dienophiles
Generally, the best dienophiles are alkenes containing electron-withdrawing substituents such as carbonyl, nitrile, and nitro groups. The feasibility of a Diels–Alder reaction depends on...