Solid State Auto-Inversion of <i>C</i>-Centrochirality: Enantioselective Total Synthesis of Furocarbazolones (−)-<i>epi</i>-Claulansine D and (−)-Claulansine D and Pyranocarbazolone (+)-<i>epi</i>-Claulansine C
作者:Shivaji B. Markad、Narshinha P. Argade
DOI:10.1021/acs.joc.7b02773
日期:2018.1.5
3-dioxolane-4-carbaldehyde, facile synthesis of (−)-epi-claulansine D was accomplished via condensation and two intramolecular cyclizations. The (−)-epi-claulansine D in the solid state exists in a metastable form, and after an induction period of 30–90 days, it underwent complete epimerization to exclusively deliver the desired natural product (−)-claulansine D in quantitative yield. The witnessed
由(E)-2-[((1-叔丁氧羰基)-1 H-吲哚-3-基]亚甲基}琥珀酸二甲酯}和(R)-2,2,5,5-四甲基-1,3-开始二氧戊环-4-甲醛,可通过缩合和两个分子内环化反应轻松合成(-)- Epi- claulansineD。固态的(-)- epi- claulansine D以亚稳态形式存在,诱导期30-90天后,它进行了完全差向异构化,以定量产量专门提供了所需的天然产物(-)-claulansine D 。C的见证倒置固态的离心力在概念上是新颖的,并且由于相对较高的晶体稳定性原因而发生。(±)/(-)- Epi- claulansine D和(±)/(-)-claulansine D的碱催化环扩展产生了(±)/(+)- epi- claulansine C,产率很高。