反应竞赛:水解与基方酸盐的分子内循环反应
Marta Ximenis1, Santiago Cañellas1, Rosa M Gomila1
1Universitat de les Illes Balears Cra. Valldemossa Km 7.5 Palma de Mallorca 07122 Spain carmen.rotger@uib.es.
RSC advances
|October 14, 2024
概括
在水中的方酸乙烯稳定性取决于邻近的组. 基本群体降低稳定性,而特定的结构使得快速循环转化为方基.
科学领域:
- 有机化学 有机化学
- 物理化学 物理化学
- 化学动力学 化学动力学
背景情况:
- 方酸乙是一种有机化合物的类别,具有潜在的应用.
- 了解它们在水性环境中的稳定性对于它们的使用至关重要.
- 水溶性行为决定了它们的保质期和反应能力.
研究的目的:
- 为了研究在水溶液中方酸盐的稳定性和水解性行为.
- 为了确定分子结构对正方体乙烯水解的影响.
- 探索邻近群体参与 (NGP) 对反应性的影响.
主要方法:
- 在一系列的pH值中,对酸乙烯解的动力学研究.
- 对水解速率和反应机制的分析.
- 通过不同的替代剂组来研究结构-活性关系.
主要成果:
- 没有或含有弱NGP的方酸以pH为9稳定.
- 水解速率常数 (kOH) 大约是10^-1 M^-1 s^-1,比squaramides快1000倍.
- 基本的NGP组 (例如,氨基) 通过合物辅助降低稳定性到pH5.
- 马位置的终端核友群促进了快速的分子内循环转化为循环方胺.
结论:
- 方酸盐的水性稳定性对结构特征,特别是NGP非常敏感.
- 水解路径和速度可以根据相邻的功能组的存在和性质来预测.
- 内分子循环化提供了一条通往新型循环方体结构的途径.
相关概念视频
Esters to Carboxylic Acids: Acid-Catalyzed Hydrolysis
2.8K
Hydrolysis of esters under acidic conditions proceeds through a nucleophilic acyl substitution. In the presence of excess water, the reaction proceeds in a reversible manner, forming carboxylic acids and alcohols.
During hydrolysis, the ester is first activated towards nucleophilic attack through the protonation of the carboxyl oxygen atom by the acid catalyst. The protonation makes the ester carbonyl carbon more electrophilic. In the next step, water acts as a nucleophile and adds to the...
During hydrolysis, the ester is first activated towards nucleophilic attack through the protonation of the carboxyl oxygen atom by the acid catalyst. The protonation makes the ester carbonyl carbon more electrophilic. In the next step, water acts as a nucleophile and adds to the...
2.8K
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
8.3K
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
8.3K
Radical Reactivity: Intramolecular vs Intermolecular
1.7K
Radical reactions can occur either intermolecularly or intramolecularly. In an intermolecular radical reaction, a nucleophilic radical adds to an electrophilic alkene or vice versa. In such reactions, the radical and generally the alkene, which is also called the radical trap, are two different molecules. Additionally, for such intermolecular reactions to occur, the radical trap must be active, present in an excess concentration, and the radical starting material must have a weak...
1.7K
Esters to Carboxylic Acids: Saponification
4.4K
Esters can be hydrolyzed to carboxylic acids under acidic or basic conditions. Base-promoted hydrolysis of esters is a nucleophilic acyl substitution reaction in which esters react with an aqueous base, followed by an acid to give carboxylic acids. This reaction is also known as saponification because it forms the basis for making soaps from fats.
The reaction requires a base in stoichiometric amounts, which participates in the reaction and is not regenerated later. So, the base acts as a...
The reaction requires a base in stoichiometric amounts, which participates in the reaction and is not regenerated later. So, the base acts as a...
4.4K
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
3.3K
Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides.
3.3K
Intramolecular Claisen Condensation of Dicarboxylic Esters: Dieckmann Cyclization
2.3K
Dieckmann cyclization is an intramolecular Claisen condensation of diesters. The reaction occurs in the presence of a base and generates a cyclic β-ketoester as the final product. Commonly, 1, 6 and 1, 7-diesters are preferred substrates for the reaction since the generated five, and six-membered cyclic β-keto esters are particularly more stable.
2.3K


