催化不对称的玻利激活循环化含有1,6-氨酸的循环赫萨氨酸
Ping Liu1, Yuki Fukui, Ping Tian
1Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
Journal of the American Chemical Society
|August 1, 2013
概括
这项研究引入了第一个铜催化不对称的化循环对循环二烯-enynes. 这种新的双重反应产生了具有高选择性的光学纯净的cis-hydrobenzofurans.
科学领域:
- 有机化学 有机化学
- 催化剂是一种催化剂.
- 不对称的合成方法
背景情况:
- 协奏反应提供了高效的合成路径,通过将多个转换结合在一个中.
- 铜催化反应是有机合成中宝贵的工具,特别是在C-B键形成中.
- 不对称的合成对于产生基纯化合物至关重要,特别是在药品中.
研究的目的:
- 开发了第一种含有1,6-enynes的铜催化不对称的化循环.
- 建立一个合过程,涉及选择性β-化和并联添加.
- 为了合成光学纯净的cis-hydrobenzofuran衍生物.
主要方法:
- 采用铜催化剂与二 (B2pin2) 作为源.
- 采用一个双重反应序列:选择性β-玻里化一个propargylic以太,其次是对一个cyclohexadienone的结合添加.
- 研究了循环化过程的区域选择性和反选择性.
主要成果:
- 实现了第一个Cu-催化不对称的1,6-enynes含有循环二烯的化循环.
- 双重反应以出色的区域选择性和反选择性进行.
- 生成光学纯净的cis-hydrobenzofuran框架,含有alkenylboronate和enone部分,可以进一步转化为桥梁和三环结构.
结论:
- 成功建立了一种新且高效的不对称并联反应,用于合成复杂的酸支架.
- 开发的方法扩大了铜催化不对称联反应的范围.
- 合成的产品作为多功能中间体,用于访问多种多环环系统.
相关概念视频
01:27Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, β-ketoesters, or β-diketones) and α,β-unsaturated carbonyl acceptors. Named after Sir Robert Robinson, who discovered it, this reaction yields a six-membered ring with three new C–C bonds (two σ bonds and one π bond).
01:17Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
01:16Cycloaddition Reactions: Overview
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
![[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.
01:29Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.