迪因斯的一般基础凝结到一个螺旋cyclopropenyl系统
Jordan Holloway1, David L Cedeño, Richard C Reiter
1Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160.
Journal of the American Chemical Society
|June 28, 2007
概括
这项研究揭示了一种新的螺旋cyclopropene合成从diynes使用 tert-butoxide. 由此产生的化合物是一种稳定的有机金属eta2-olefin五碳化合物.
科学领域:
- 有机化学 有机化学
- 有机金属化学 有机金属化学
背景情况:
- 环烯化合物是具有独特反应性的紧张循环分子.
- 螺旋环烯是一种螺旋环烯的子类,具有螺旋环结构.
- 螺旋cyclopropenes的合成是具有挑战性的,很少有报告的例子.
研究的目的:
- 开发一种新的合成途径,以获得螺旋cyclopropene化合物.
- 描述中间基离子和最终的螺旋cyclopropene产品.
- 探索合成的螺旋cyclopropene与有机金属前体的反应性.
主要方法:
- 1,6-heptadiyne与三氧化和18-crown-6在低温THF中的反应.
- 电子偏磁共振 (EPR) 谱学用于基离子离子的表征.
- 降压蒸用于产品隔离.
- 用螺旋cyclopropene对六碳烯进行激光照射.
主要成果:
- 形成一种绿色的EPR活性溶液,该溶液归因于7,14-di-trans-1,5-[14]annuldiyne的离子基.
- 变色为深紫色,在变暖时失去EPR活性.
- 分离了spiro[2.6]nona-2,6,8-triene,这是一个新型的spirocyclopropene.
- 通过激光照射合成稳定的eta2-olefin五碳化合物.
结论:
- 建立了一种通用基缩方法,用于从各种二烯酸中合成螺旋cyclopropenyl系统.
- 该研究报告了第二个已知的螺旋cyclopropene化合物.
- 合成的螺旋cyclopropene 作为稳定的有机金属复合物的宝贵前体.
相关概念视频
[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.
Diels–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.
Diels–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.
Cycloaddition 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.
Structure of Conjugated Dienes
Introduction
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview
Cyanohydrins are compounds that contain –CN and –OH groups on the same carbon atom. They are formed by the nucleophilic addition of the cyanide ions to the carbonyl group. Cyanide ions are highly basic and nucleophilic and can be generated from HCN under aqueous conditions. However, since HCN is a weak acid, the number of cyanide ions generated is very small. Hence, a small amount of base or KCN/NaCN is added to HCN to increase the concentration of the cyanide ions in the reaction mixture.


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