Aqueous Titanium Trichloride Promoted Reductive Cyclization of
<i>o</i>
‐Nitrostyrenes to Indoles: Development and Application to the Synthesis of Rizatriptan and Aspidospermidine
作者:Shuo Tong、Zhengren Xu、Mathias Mamboury、Qian Wang、Jieping Zhu
DOI:10.1002/anie.201505713
日期:2015.9.28
TiCl3 solution at room temperature afforded indoles through a formal reductive C(sp2)–H amination process. A range of functions such as halides (Cl, Br), carbonyl (ester, carbamate), cyano, hydroxy, and amino groups were tolerated. From β,β‐disubstituted o‐nitrostyrenes, 2,3‐disubstituted indoles were formed by a domino reduction/cyclization/migration process. Mild conditions, simple experimental procedure
在室温下用TiCl 3水溶液处理邻硝基苯乙烯,通过正式的还原性C(sp 2)–H胺化过程获得了吲哚。可以耐受多种功能,例如卤化物(Cl,Br),羰基(酯,氨基甲酸酯),氰基,羟基和氨基。通过多米诺还原/环化/迁移过程,由β,β-二取代的邻-硝基苯乙烯形成2,3-二取代的吲哚。温和的条件,简单的实验程序,易于接近的起始原料以及良好至极佳的收率是目前转化的特征。该方法学被用作简明合成利扎曲普坦和正式全合成阿斯哌啶的关键步骤。