相关实验视频
Updated: Jan 29, 2026

11:22
The α-test: Rapid Cell-free CD4 Enumeration Using Whole Saliva
Published on: May 16, 2012
14.3K
硫烯酸二氧化的选性α,α-化
Lucas G Furniel1, Kauê C Capellaro1, Viktor S Câmara1
1Chemistry Institute of São Carlos, University of São Paulo, CEP 13560-970, São Carlos, SP 05508-220, Brazil.
Organic letters
|January 28, 2026
概括
这项研究首次引入了α-carbonylsulfoxonium ylides的第一个enantioselective化. 研究人员使用新奇的性方法实现了宝石二化化合物的高产量和酶选择性.
科学领域:
- 有机化学 有机化学
- 不对称的合成方法
- 化化学 化化学
背景情况:
- α-Carbonylsulfoxonium化物是多用途的合成中间体.
- 石质二化化合物的酶选择性合成仍然是一个挑战.
- 开发新的性催化剂和试剂对于不对称转换至关重要.
研究的目的:
- 开发了第一个对α-carbonylsulfoxonium ylides的第一个enantioselectiveα,α-chlorofluorination.
- 探索两种不同的反应模式来实现这种转变.
- 合成有价值的宝石二化化合物,具有高度的立体化学控制.
主要方法:
- 作为指导小组,使用了奇拉性aminosulfoxonium化物.
- 采用了一种从辛科纳类化合物in situ生成的性化试剂.
- 研究了化和化两种互补的反应途径.
主要成果:
- 成功地实现了α-carbonylsulfoxonium ylides的选性α,α-化化.
- 合成了25种宝石二化化合物的例子,包括化产品.
- 获得的产品具有良好的产量 (高达90%) 和高反选择性 (高达96:4er).
结论:
- 证明了第一个成功的对α-carbonylsulfoxonium ylides的酶选择性α,α-化.
- 建立了高效的合成路径,利用性辅助剂和试剂.
- 为进一步的合成应用提供了获取有价值的性宝石二化构建块的机会.
相关概念视频
α-Alkylation of Ketones via Enolate Ions
3.8K
Ketones with α protons are deprotonated by strong bases like lithium diisopropylamide (LDA) to form enolate ions. The anion is stabilized by resonance, and its hybrid structure exhibits negative charges on the carbonyl oxygen and the α carbon. This ambident nucleophile can attack an electrophile via two possible sites: the carbonyl oxygen, known as O-attack, or the α carbon, known as C-attack. The nucleophilic attack via the carbanionic site is preferred. This is due to the...
3.8K
Factors Affecting α-Alkylation of Ketones: Choice of Base
3.6K
α-Alkylation of ketones is achieved in the presence of alkyl halides and a base. The reaction proceeds via the formation of an enolate ion followed by nucleophilic substitution. The choice of base employed is essential as it is the key factor in determining the reaction outcome.
The reaction involving bases like EtO− whose conjugate acid EtOH (pKa = 15.9) is stronger than the ketone (pKa = 19.2) results in an equilibrium mixture with higher ketone concentration. As a consequence,...
The reaction involving bases like EtO− whose conjugate acid EtOH (pKa = 15.9) is stronger than the ketone (pKa = 19.2) results in an equilibrium mixture with higher ketone concentration. As a consequence,...
3.6K
Reactions of α-Halocarbonyl Compounds: Nucleophilic Substitution
3.9K
Nucleophilic substitution in α-halocarbonyl compounds can be achieved via an SN2 pathway. The reaction in α-haloketones is generally carried out with less basic nucleophiles. The use of strong basic nucleophiles leads to the generation of α-haloenolate ions, which often participate in other side reactions.
3.9K
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
4.9K
By replacing an α-hydrogen with a halogen, acid-catalyzed α-halogenation of aldehydes or ketones yields a monohalogenated product
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
4.9K
Base-Promoted α-Halogenation of Aldehydes and Ketones
4.2K
α-Halogenation of aldehydes and ketones is a reaction involving the substitution of α hydrogens with halogens in the presence of a base. The reaction begins with the abstraction of α hydrogen by the base to produce a nucleophilic enolate ion. This intermediate undergoes a subsequent nucleophilic substitution with the halogen to produce a monohalogenated carbonyl compound. If the starting substrate has more than one α hydrogen, it is difficult to stop the reaction...
4.2K
α-Halogenation of Carboxylic Acid Derivatives: Overview
4.1K
Unlike aldehydes and ketones, carboxylic acids do not readily participate in α halogenation reactions via enols or enolate intermediates. However, α-halogenated acids are obtained through other methods. One of the approaches is the Hell–Volhard–Zelinsky (HVZ) reaction, wherein the carboxylic acid is treated with halogen in the presence of PBr3. It involves the conversion of acid to acid halide, which exists in equilibrium with its enol form. The enol attacks the...
4.1K

