A Practical Synthesis of Enantiopure 4,5-Dihydroisoxazole-5-carboxylic Acids
The 1,3-dipolar cycloaddition of a variety of aromatic and aliphatic nitrile oxides to 2,5-trans-2,5-diphenylpyrrolidine derived acrylamide and cinnamamide efficiently affords the corresponding 4,5-dihydroisoxazole-5- carboxamides in a highly regio- and stereoselective manner. The cycloaddition of a...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2005 |
| País: | España |
| Institución: | Universidad de Sevilla (US) |
| Repositorio: | idUS. Depósito de Investigación de la Universidad de Sevilla |
| OAI Identifier: | oai:idus.us.es:11441/70420 |
| Acceso en línea: | https://hdl.handle.net/11441/70420 https://doi.org/10.1055/s-2005-921894 |
| Access Level: | acceso abierto |
| Palabra clave: | Asymmetric synthesis Cycloadditions Heterocycles Isoxazolines Nitrile oxides |
| Sumario: | The 1,3-dipolar cycloaddition of a variety of aromatic and aliphatic nitrile oxides to 2,5-trans-2,5-diphenylpyrrolidine derived acrylamide and cinnamamide efficiently affords the corresponding 4,5-dihydroisoxazole-5- carboxamides in a highly regio- and stereoselective manner. The cycloaddition of aliphatic nitrile oxides to the analogue methacrylamide proceeds also smoothly to afford the expected cycloadducts in moderate yields and very high regio- and stereoselectivity. In sharp contrast, aromatic nitrile oxides react with the same amide to afford 5-methyl-4,5-dihydroisoxazole-5-carboxamides in higher yields but as near 1:1 mixtures of diastereoisomers. Acid hydrolysis of these products afforded enantiopure 4,5-dihydroisoxazole-5-carboxylic acids. © Georg Thieme Verlag Stuttgart. |
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