Highly Efficient Formal [2+2+2] Strategy for the Rapid Construction of Polycyclic Spiroindolines: A Concise Synthesis of 11‐Demethoxy‐16‐
<i>epi</i>
‐myrtoidine
the stereoselective elaboration of polycyclic indole alkaloids is described. Upon treatment with the catalyst InCl3 (5 mol %), tryptamine‐derived enamides reacted readily with methylene malonate, thus enabling rapid and gram‐scale access to versatile tetracyclic spiroindolines with excellent diastereoselectivity (21 examples, up to 95 % yield, up to d.r.>95:5). This strategy provides a concise approach
Remote Ester Groups Switch Selectivity: Diastereodivergent Synthesis of Tetracyclic Spiroindolines
作者:Jun Zhu、Yong Liang、Lijia Wang、Zhong-Bo Zheng、K. N. Houk、Yong Tang
DOI:10.1021/ja503117q
日期:2014.5.14
Stereocontrol in the synthesis of structurally complex molecules, especially those with all-carbon quaternary stereocenters, remains a challenge. Here, we reported the preparation of a class of tetracyclic cyclopenta-fused spiroindoline skeletons through Cu(II)-catalyzed intramolecular [3 + 2] annulation reactions of donor-acceptorcyclopropanes with indoles. Both cis- and trans-diastereomers of tetracyclic