Chemistry Department, Faculty of Science, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait.
J Org Chem. 2010 Jul 2;75(13):4508-13. doi: 10.1021/jo100679d.
An efficient approach to highly rigid macrocyclic bisazetidinones with interesting structural feature was achieved via sequential Staudinger ketene-imine cycloaddition of o-allyloxyphenoxyketene and bis-arylidenediamines followed by RCM. The ketene-imine cycloaddition afforded the corresponding bis-o-allyloxyphenoxyazetidinones as the cis-cis diastereomers, exclusively obtained as a mixture of cis-syn-cis and cis-anti-cis. RCM of the latter using Grubbs' catalysts afforded good yields of the corresponding novel macrocyclic bisazetidinones. The cis-anti-cis bisazetidinones are readily identified by (1)H NMR using Eu(hfc)(3) chiral shift reagent. (1)H NMR indicated the high shielding effect of the aryl substituents on one of the ortho-H's of the condensed phenylene ring, and VT (1)H NMR indicates the highly restricted rotation of the aryl groups, thus offering a highly rigid system.
一种高效的方法，通过 o-烯丙氧基苯氧基烯酮和双芳亚胺的顺序 Staudinger 酮烯胺环加成，然后进行 RCM，得到具有有趣结构特征的高度刚性的大环双氮杂环丁酮。酮烯胺环加成以顺式-顺式二非对映异构体的形式提供相应的双-o-烯丙氧基苯氧基氮杂环丁酮，作为混合物仅获得顺式-顺式和顺式-反式。使用 Grubbs 催化剂对后者进行 RCM 可得到相应的新型大环双氮杂环丁酮的良好产率。通过使用 Eu(hfc)(3)手性位移试剂的 (1)H NMR 可以容易地鉴定顺式-反式双氮杂环丁酮。(1)H NMR 表明稠合的亚苯基环上的一个邻位-H 的芳基取代基的高屏蔽效应，并且 VT (1)H NMR 表明芳基的高受限旋转，从而提供了一个高度刚性的系统。
