Generation of functionalized azomethine ylides and their application to stereoselective heterocycle synthesis: an equivalent process of C-unsubstituted nitrile ylide cycloaddition reaction
作者:Keisuke Kawashima、Akikazu Kakehi、Michihiko Noguchi
DOI:10.1016/j.tet.2006.12.004
日期:2007.2
Abstract The synthetic process equivalent to C-unsubstituted (CH) nitrile ylides cycloaddition reaction is achieved via cycloaddition of NH-azomethine ylide and the following fission reaction of the cycloadducts under acidic conditions. Cycloaddition of NH-azomethine ylide generated by a thermal 1,2-prototropy in 4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carbaldehyde system with maleimides provides proline
摘要 通过NH-偶氮甲碱叶立德的环加成和随后的环加合物在酸性条件下的裂变反应,实现了相当于C-未取代(CH)腈叶立德环加成反应的合成过程。在 4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carbaldehyde 系统中由热 1,2-prototropy 生成的 NH-azomethine 叶立德与马来酰亚胺在极其温和的条件下进行环加成反应提供脯氨酸衍生物。在 85 °C 下在 AcOH 中加热它们的加合物会导致脯氨酸和杂环部分之间的 C-C 键断裂,得到母体杂环系统和脱氢脯氨酸衍生物,它被认为是 C-未取代 (CH) 腈叶立德的环加合物。这种环加成裂变反应序列可应用于一锅三组分反应。