XY–ZH systems as potential 1,3-dipoles. Part 2. Oxime cycloadditions: formation of 2 : 1 adducts
作者:Ronald Grigg、Maurice Jordan、Aant Tangthongkum、Frederick W. B. Einstein、Terry Jones
DOI:10.1039/p19840000047
日期:——
Cycloaddition of aldehyde and ketone oximes are shown to give mixtures of all possible isoxazolidine regioisomers and stereoisomers. The products are 2 : 1 adducts with the second molecule of the di-polarophile attached to the isoxazolidine N-atom. The stereochemistry of the major isomer from benzaldehyde oxime and acrylonitrile was established by an X-ray crystal structure analysis. The cycloaddition
醛和酮肟的环加成显示出所有可能的异恶唑烷区域异构体和立体异构体的混合物。产物是2:1的加合物,其第二亲双性分子附着在异恶唑烷的N-原子上。通过X射线晶体结构分析建立了苯甲醛肟和丙烯腈的主要异构体的立体化学。环加成反应被2,4-二硝基苯酚弱催化,在乙腈中进行得最好。更多极性溶剂稍微偏爱5-异恶唑烷区域异构体。讨论了反应机理。