active ester bond through the classic organic name reaction, Baeyer–Villiger (BV) oxidation, and thus acetal esters and aryl esters were produced in high yields (up to 99%) at room temperature. Next, K2CO3 catalyzed the alcoholysis of the resulting ester products at 45 °C, affording various useful chemical platforms in excellent yields (up to 99%), such as phenols and multifunctional esters. This method
开发了一种用于木质素模型化合物的C–C键裂解的高效方法。惰性Ç α -C β或C α -C苯基的氧化木质素模型化合物通过键的经典有机名称反应成功地转化为活性酯键,拜尔-维利格(BV)的氧化,因此缩醛酯和芳基酯是在室温下以高收率(高达99%)生产。接下来,K 2 CO 3催化所得酯产物在45°C下的醇解反应,从而以优异的收率(高达99%)提供了各种有用的化学平台,例如苯酚和多功能酯。该方法使用可商购的试剂,不含过渡金属且简单,但高效,并且涉及温和的反应条件。
Electrochemical generation and reactions of acyloxytriphenylphosphonium ions
undivided cell, of Ph3P in the presence of a carboxylic acid in CH2Cl2 containing 2,6-lutidinium perchlorate as the supporting electrolyte was shown to generate the corresponding acyloxyphosphonium ion, Ph3P+-OCOR, which was converted in situ to esters, amides, and β-lactams under mild conditions.
结果表明,在羧酸存在下的CH 2 Cl 2中,含高氯酸2,6-lut啶鎓作为辅助电解质的PH 3 P在不分隔的电池中恒流电解会生成相应的酰氧基phosph离子Ph 3 P + -OCOR,在温和条件下原位转化为酯,酰胺和β-内酰胺。
Efficient Transesterification/Acylation Reactions Mediated by <i>N</i>-Heterocyclic Carbene Catalysts
作者:Gabriela A. Grasa、Tatyana Güveli、Rohit Singh、Steven P. Nolan
DOI:10.1021/jo0267551
日期:2003.4.1
Imidazol-2-ylidenes, a family of N-heterocyclic carbenes (NHC), are efficient catalysts in the transesterification involving numerous esters and alcohols. Low catalyst loadings of aryl- or alkyl-substituted NHC catalysts mediate the acylation of alcohols with enol acetates in short reaction times at room temperature. Commercially available and more difficult to cleave methyl esters react with primary
Mixed alkoxide/aryloxide clusters are long-lived and milder than previously reported esterinterchange catalysts. They completely transform difficult substrates in a single synthetic operation with lower catalyst and reagent ester loadings. In addition to superior activities, these mixed clusters are kinetically less basic toward enolizable esters.
Mild conversion of primary carboxamides into carboxylic esters
作者:Pier Lucio Anelli、Marino Brocchetta、Daniela Palano、Massimo Visigalli
DOI:10.1016/s0040-4039(97)00350-x
日期:1997.3
Primary carboxamides are converted into the corresponding alkyl carboxylates by treatment with dimethylformamide dimethylacetal in the appropriate alcohol at 25–45 °C. Yields are very good to excellent.