1,3-二博拉-2,4-二二旋-1,3-二基的激素类型的反应性
Hideki Amii1, Lidija Vranicar, Heinz Gornitzka
1Laboratoire Hétérochimie Fondamentale et Appliquée, UMR CNRS 5069, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse Cedex 04, France.
Journal of the American Chemical Society
|February 5, 2004
概括
稳定的1,3--2,4-二二旋-1,3-二呈现出类似激素的行为. 这可以通过其与三甲基化物和基甲的反应来证明,形成独特的附加物.
科学领域:
- 有机金属化学 有机金属化学
- 化学 化学
- 酸盐化学 酸盐化学
背景情况:
- 稳定的含化合物在材料科学和催化中至关重要.
- 了解新型-异环的反应性是开发新化学转换的关键.
- 1,3--2,4-二二环丁-1,3-二系统具有独特的电子和结构特征.
研究的目的:
- 为了研究稳定的1,3--2,4-二二旋-1,3-二的反应性和电子性质.
- 探索这种-杂环中的激素类型行为潜力.
- 用常见的激素捕捉剂来表征反应产物.
主要方法:
- 合成和表征的1,3--2,4-diphosphoniocyclobutane-1,3-diyl.diyl 的时间.
- 用三甲基化物和三甲进行反应研究.
- 由此产生的添加物的光谱分析 (NMR,X射线晶体学).
主要成果:
- 稳定的1,3--2,4-二二环-1,3-二经过自发的1,3-添加与三甲基化物形成一个转 adduct.
- 与基甲的反应产生了B-spiro衍生物,表明了基因类型的反应性.
- 通过空间和通过键的B-B相互作用并不能阻止这种观察到的激进行为.
结论:
- 尽管其结构稳定,但1,3--2,4-二二氧化-1,3-二烯具有显著的激素类型反应性.
- 这种反应性允许新型有机金属添加物和螺旋环化合物的形成.
- 这些发现为在合成化学中利用-异环开辟了新的途径.
相关概念视频
E2 Reaction: Stereochemistry and Regiochemistry
Elimination reactions of alkyl halides can yield one or more alkenes depending on the specific regiochemical and stereochemical considerations. While the regiochemistry of the reaction governs the location of the double bond in the product, the stereochemical requirements often influence the geometry.
When a substrate with two different β hydrogens undergoes an E2 elimination, the presence of a strong base can yield two regioisomeric alkenes. The more-substituted alkene is the major product and...
When a substrate with two different β hydrogens undergoes an E2 elimination, the presence of a strong base can yield two regioisomeric alkenes. The more-substituted alkene is the major product and...
Conjugate Addition to α,β-Unsaturated Carbonyl Compounds
α,β-Unsaturated carbonyl compounds are molecules bearing a carbonyl and alkene functionality in conjugation with each other. The conjugation in the molecule leads to three resonance structures. The hybrid form exhibits two probable electrophilic sites: the carbonyl carbon and the β carbon.
Reactions at the Benzylic Position: Oxidation and Reduction
The benzylic position describes the position of a carbon atom attached directly to a benzene ring. Benzene by itself does not undergo oxidation. In contrast, the benzylic carbon is quite reactive in the presence of strong oxidizing agents such as KMnO4 or H2CrO4. Therefore, alkylbenzenes are readily oxidized to benzoic acid, irrespective of the type of alkyl groups.
C–C Bond Cleavage: Retro-Aldol Reaction
The reverse of the aldol addition reaction is called the retro-aldol reaction. Here, the carbon–carbon bond in the aldol product is cleaved under acidic or basic conditions to form two molecules of carbonyl compounds. The mechanism of the reaction consists of three steps.
In the first step, as depicted in Figure 1, the base deprotonates the β-hydroxy ketone at the hydroxyl group to form an alkoxide ion.
In the first step, as depicted in Figure 1, the base deprotonates the β-hydroxy ketone at the hydroxyl group to form an alkoxide ion.
Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)
α,β-Unsaturated carbonyl compounds with two electrophilic sites, the carbonyl carbon, and the β carbon, are susceptible to nucleophilic attack via two modes: conjugate or 1,4-addition and direct or 1,2-addition.
Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon.
Direct addition products are formed faster owing to...
Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon.
Direct addition products are formed faster owing to...
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.
![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)

