Yu Zhi-Xiang, Houk K N
Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.
J Am Chem Soc. 2003 Nov 12;125(45):13825-30. doi: 10.1021/ja0376487.
Density functional theory studies of intramolecular ene-like (or the so-called 1,3-dipolar ene) reactions between nitrile oxides and alkenes (Ishikawa, T.; Urano, J.; Ikeda, S.; Kobayashi, Y.; Saito, S. Angew. Chem., Int. Ed. 2002, 41, 1586) show that this reaction is a three-step process involving a stepwise carbenoid addition of nitrile oxide to form a bicyclic nitroso compound, followed by a retro-ene reaction of the nitrosocyclopropane intermediate. The competitive reactions, either the intramolecular (3+2) reactions between nitrile oxides and alkenes or the intermolecular dimerizations of nitrile oxides to form furoxans, can overwhelm the intramolecular 1,3-dipolar ene reactions when the tether joining the nitrile oxide and alkene is elongated or some substituents such as trimethylsilyl are absent.
密度泛函理论对腈氧化物与烯烃之间分子内类烯反应（即所谓的1,3-偶极烯反应）的研究（石川，T.；浦野，J.；池田，S.；小林，Y.；斋藤，S.《德国应用化学》，国际版，2002年，41卷，1586页）表明，该反应是一个三步过程，包括腈氧化物逐步以类卡宾形式加成形成双环亚硝基化合物，随后亚硝基环丙烷中间体发生逆烯反应。当连接腈氧化物和烯烃的系链伸长或不存在某些取代基（如三甲基硅基）时，腈氧化物与烯烃之间的分子内(3 + 2)反应或腈氧化物分子间二聚形成呋咱的竞争反应，可能会超过分子内1,3-偶极烯反应。
