Regio- and Stereoselectivity of Captodative Olefins in 1,3-Dipolar Cycloadditions. A DFT/HSAB Theory Rationale for the Observed Regiochemistry of Nitrones
作者:Rafael Herrera、Arumugam Nagarajan、Miguel A. Morales、Francisco Méndez、Hugo A. Jiménez-Vázquez、L. Gerardo Zepeda、Joaquín Tamariz
DOI:10.1021/jo001393n
日期:2001.2.1
Captodative olefins 1-acetylvinyl carboxylates proved to be highly regioselective dipolarophiles in 1,3-dipolar cycloadditon to propionitrile oxide, arylphenylnitrile imines, diazoalkanes, and nitrones to yield the corresponding 5-substituted heterocycles. The addition of the latter was also stereoselective, being slightly susceptible to steric demand of the carboxylate substituent in the olefin. All atempts
巯基化烯烃1-乙酰基乙烯基羧酸盐在1,3-偶极环丙二酸,丙腈氧化物,芳基苯基腈亚胺,重氮烷烃和硝酮中具有高区域选择性的双极性亲油性,可生成相应的5-取代的杂环。后者的添加也是立体选择性的,对烯烃中羧酸根取代基的空间需求稍有敏感性。在还原条件下所有试图裂解异恶唑烷NO键的尝试均告失败,从而提供了具有侧基还原作用的多种产物。由于预测了相反的方向,FMO理论未能成功解释用硝酮观察到的区域选择性。最近建立的DFT / HSAB理论模型能够合理化这种区域选择性,