Expedient Introduction of β-Methoxyacrylate Unit onto 3-Substituted Indoles and Application of the Resulting Indole-Dienes in Organocascade toward Indolino-Polycyclics
作者:Beibei Guo、Luo Ge、Guanxin Huang、Long Zhao、Jie Chen、Weiguo Cao、Xiaoyu Wu
DOI:10.1002/adsc.201500613
日期:2015.12.14
An efficient methodology for introducing a β-alkoxy acrylate unit onto the indolic C-2 position of 3-substituted indoles has been realized by oxidative radical alkylation of indoles with a xanthate bearing dialkyl acetal functionality and subsequent elimination of alcohol by treatment with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The indole-dienes thus prepared are quite stable and can be stored at
通过将带有黄原酸酯的吲哚的氧化自由基烷基化并带有带有二烷基乙缩醛官能团的黄原酸酯,然后通过用1,8处理来消除醇,已经实现了将β-烷氧基丙烯酸酯单元引入3-取代的吲哚的吲哚C-2位置的有效方法。 -二氮杂双环[5.4.0]十一碳-7-烯(DBU)。这样制得的吲哚二烯是相当稳定的,可以在室温下保存数月而没有明显的变质。下一步,将吲哚二烯成功地与麦克米兰的咪唑啉酮和三氯乙酸(TCA)催化的炔丙基醛进行不对称级联反应,从而以良好的收率和优异的ee收率得到四环螺二吲哚啉或三环烃唑。s。该级联反应的实用性通过克制规模低至1 mol%催化剂负载量的四环螺二氢吲哚产物以及将该螺二氢吲哚化合物进一步精制为有价值的中间体进行生物碱合成来证明。