催化C-H键功能化与II:空气氧化废除的英多尔的氧化
Eric M Ferreira1, Brian M Stoltz
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Journal of the American Chemical Society
|August 9, 2003
概括
这项研究详细介绍了一种催化反应,利用氧气形成环. 在这种高效的氧化循环化过程中,氨酸连接体电子是实现良好产量的关键.
科学领域:
- 有机化学 有机化学
- 催化剂是一种催化剂.
- 异环化学 异环化学
背景情况:
- 印度衍生物是药品和天然产品中重要的结构动图.
- 对于英多尔功能化的高效合成方法的需求非常高.
- 催化C-H激活为构建复杂分子提供了强大的工具.
研究的目的:
- 开发一种新的催化有氧氧化取消印的新型有氧化取消.
- 为了研究反应参数,特别是胺联体对循环化效率的影响.
- 阐明反应机制,包括分子氧作为氧化剂的作用.
主要方法:
- 帕拉催化有氧氧化取消反应.
- 系统地改变皮里丁配体以研究电子效应.
- 机械研究,包括中间分析和计算研究 (隐含).
主要成果:
- 多种类型的醇经历了成功的氧化取消.
- 发现,胺联体的电子性质对于反应效率至关重要.
- 取得了良好的产量,克服了潜在的氧化分解途径.
- 分子氧被证实是Pd0的有效直接氧化剂.
结论:
- 开发的方法为合成英多尔衍生物提供了一条有效的途径.
- 皮里丁连接体的电子调节对于优化催化氧化循环是至关重要的.
- 反应通过一个机制进行,包括合,迁移插入和β-消除.
相关概念视频
01:57Preparation of Diols and Pinacol Rearrangement
Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
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.
01:11ortho–para-Directing Activators: –CH3, –OH, –NH2, –OCH3
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
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).
01:29Diels–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.