Intramolecular Pictet-Spengler reaction of Nb-Alkoxytryptamines. 4. A study towards diastereocontrol in the synthesis of tetracyclic eudistomins
作者:Jan H. van Maarseveen、Hans W. Scheeren、Chris G. Kruse
DOI:10.1016/s0040-4020(01)80376-8
日期:1993.3
methylated derivative was also synthesized giving the interesting cis/trans pentacyclic spiro compounds 19 and 20. These results are interpreted in terms of a kinetically favoured electrophilic attack at the indole-3 position, whereas β-carboline formation is the result of a slower route via electrophilic attack at the indole-2 position.
描述了在合成四环大黄连素中分子内Pictet-Spengler缩合的非对映选择性。N b-烷氧基色胺15a–m与不同大小的基团R 2合成。7成员草硫氮杂ze环的闭合以66–98%的产率完成。使用分子内方法,可以实现非天然反式异构体的非对映选择性。还合成了吲哚甲基化衍生物,得到了有趣的顺式/反式五环螺化合物19和20。这些结果被解释为在吲哚3位置的动力学上有利于亲电子的攻击,而β-咔啉的形成是在吲哚2位置上通过亲电子攻击的较慢途径的结果。