Ring transformations of heterocyclic compounds.<b>XXI</b>. Diastereoselective built-up of an aroylcyclohexadiene moiety as second spiro-connected ring at spiroindolines by pyrylium ring transformation
作者:Thomas Zimmermann
DOI:10.1002/jhet.5570390202
日期:2002.3
cycloalkene or a heterocyclic system. These diastereoselective 2,5-[C4+C2] pyrylium ring transformations are carried out in the presence of triethylamine/acetic acid in boiling ethanol to give the dispiroindolines 4 with a trans configuration of the more bulky substituents at the cyclohexadiene ring. By the same type of transformation the dispiro compounds 7/10 with an additional fused benzene ring are obtained
2,4,6-三芳基吡啶鎓高氯酸盐1与由相应的甲基吲哚盐2原位生成的亚甲基二氢吲哚3 反应,该亚甲基二氢吲哚盐3与环烷烃,苯甲酰化环烯烃或杂环系统螺旋稠合。这些非对映选择性的2,5- [C 4 + C 2 ]吡喃鎓环转化是在三乙胺/乙酸的存在下于沸腾的乙醇中进行的,以得到在环己二烯环上具有更大体积取代基的反式构型的二螺二吲哚啉4。通过相同类型的转化,双螺化合物7/10从吡喃鎓盐1a和6/9(苯并稠合的3的类似物)获得带有额外的稠合苯环的苯并稠合类似物。讨论了转化产物的光谱数据及其形成方式。