A general strategy for the synthesis of indoloquinolizine alkaloids <i>via</i> a cyanide-catalyzed imino-Stetter reaction
作者:Eunjoon Park、Cheol-Hong Cheon
DOI:10.1039/c7ob02691a
日期:——
A new strategy applicable to the synthesis of indoloquinolizine natural products has been developed. A cyanide-catalyzed intramolecular imino-Stetter reaction of aldimines, derived from 2-aminocinnamic acid derivatives and 2-pyridinecarboxaldehydes, provided indole-3-acetic acid derivatives bearing a pyridyl ring at the 2-position. Reduction of the carboxylic acid moiety to an alcohol followed by activation
The indole C5-selective bromination of indolo[2,3-a]quinolizidine alkaloids by adding nearly equimolar amounts of Br3 ⋅ PyH and HCl in MeOH is disclosed. The resulting reaction plausibly proceeds through an indoline intermediate by the nucleophilic addition of MeOH to the C3-brominated indolenine intermediate. These simple, mild, and metal-free conditions are suitable for late-stage chemical conversions
公开了通过在MeOH中添加几乎等摩尔量的Br 3 ·PyH和HCl来对吲哚并[2,3- a ]喹啉西啶生物碱进行吲哚C5选择性溴化。通过将MeOH亲核加成至C3-溴化吲哚啉中间体,所得反应似乎通过二氢吲哚中间体进行。这些简单、温和且不含金属的条件适用于全合成和药物化学中的后期化学转化。