Intra- and intermolecular thermal transformations of 2-acyl- and 2-alkoxycarbonyl-N-phthalimidoaziridines
摘要:
Heating 2-acyl- and 2-alkoxycarbonyl-N-phthalimidoaziridines leads to substituted oxazoles in 45-65% yield. Only esters of oxazolecarboxylic acids are formed when the aziridine contains acyl and alkoxy groups. The thermolysis of the same aziridines in the presence of N-phenylmaleimide and the dimethyl ester of acetylenedicarboxylic acid gives both oxazoles and the products of 1,3-dipolar cycloaddition from aziridines with two substituents at the carbon atoms but only oxazoles from trisubstituted aziridines.
An I2-promoted formal [3+2] cycloaddition for access to oxazoles has been demonstrated. This is the first example of a Lewis acid-promoted formal [3+2] cycloaddition of isocyanides with methyl ketones involves...
Silver‐Induced [3+2] Cycloaddition of Isocyanides with Acyl Chlorides: Regioselective Synthesis of 2,5‐Disubstituted Oxazoles
作者:Jian‐Quan Liu、Xuanyu Shen、Andrey Shatskiy、Enlong Zhou、Markus D. Kärkäs、Xiang‐Shan Wang
DOI:10.1002/cctc.201900965
日期:2019.9.5
A silver‐induced cycloaddition of isocyanides with acyl chlorides has been developed. This transition metal‐catalyzed strategy provides an effective and scalable approach for the formation of 2,5‐disubstituted oxazoles in good to high yields. The employed silver‐based MOF catalyst can be efficiently recycled without compromising the yield.
Carboxylic Acid Salts as Dual‐Function Reagents for Carboxylation and Carbon Isotope Labeling
作者:Shuo Wang、Igor Larrosa、Hideki Yorimitsu、Gregory J. P. Perry
DOI:10.1002/anie.202218371
日期:2023.3.27
The potassium salt of triphenylacetic acid is developed as a combined source of CO2 and base/metalating agent. This method avoids specialized equipment and is used in the carboxylation of a range of compound classes. This provides a mechanistically distinct approach to carboxylation that has also been applied in carbon isotopelabeling.
三苯乙酸的钾盐被开发为 CO 2和碱/金属化剂的组合来源。该方法无需专用设备,可用于一系列化合物类别的羧化。这提供了一种机械上不同的羧化方法,该方法也已应用于碳同位素标记。
Carbon Dioxide as the C1 Source for Direct C−H Functionalization of Aromatic Heterocycles
作者:Oleg Vechorkin、Nathalie Hirt、Xile Hu
DOI:10.1021/ol101450u
日期:2010.8.6
A simple and straightforward method has been developed for the direct carboxylation of aromatic heterocylces such as oxazoles, thiazoles, and oxadiazoles using CO(2) as the C1 source. The reactions require no metal catalyst and only Cs(2)CO(3) as the base. A good functional group tolerance is achieved.
Intra- and intermolecular thermal transformations of 2-acyl- and 2-alkoxycarbonyl-N-phthalimidoaziridines
作者:M. A. Kuznetsov、V. V. Voronin
DOI:10.1007/s10593-011-0738-8
日期:2011.5
Heating 2-acyl- and 2-alkoxycarbonyl-N-phthalimidoaziridines leads to substituted oxazoles in 45-65% yield. Only esters of oxazolecarboxylic acids are formed when the aziridine contains acyl and alkoxy groups. The thermolysis of the same aziridines in the presence of N-phenylmaleimide and the dimethyl ester of acetylenedicarboxylic acid gives both oxazoles and the products of 1,3-dipolar cycloaddition from aziridines with two substituents at the carbon atoms but only oxazoles from trisubstituted aziridines.