Iridium-Catalyzed Enantioselective Intermolecular Indole C2-Allylation
Iridium-Catalyzed Enantioselective Intermolecular Indole C2-Allylation
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铱催化对映选择性分子间吲哚 C2-烯丙基化
DOI：
10.1002/ange.202001956
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发表时间：
2020
影响因子：
--
通讯作者：
Rossi-Ashton J
中科院分区：
文献类型：
--
作者：
Rossi-Ashton J
本文首次报道了3 -取代吲哚分子间C2 -烯丙基化反应。这种无导向基团的方法依赖于手性Ir - （P，烯烃）配合物和Mg(ClO4)2Lewis酸催化剂体系来促进烯丙基取代，提供典型的高收率（40 - 99%）和对映选择性（83 - 99% ee）的C2 -烯丙基化产物，具有良好的区域控制。实验研究和DFT计算表明，反应是通过直接的C2 -烯丙基化进行的，而不是C3 -烯丙基化之后的原位迁移。在吲哚- C3位置的空间拥塞和改善的π -π堆叠相互作用被认为是C2选择性的主要贡献者。
The enantioselective intermolecular C2‐allylation of 3‐substituted indoles is reported for the first time. This directing group‐free approach relies on a chiral Ir‐(P, olefin) complex and Mg(ClO4)2Lewis acid catalyst system to promote allylic substitution, providing the C2‐allylated products in typically high yields (40–99 %) and enantioselectivities (83–99 %ee) with excellent regiocontrol. Experimental studies and DFT calculations suggest that the reaction proceeds via direct C2‐allylation, rather than C3‐allylation followed by in situ migration. Steric congestion at the indole‐C3 position and improved π–π stacking interactions have been identified as major contributors to the C2‐selectivity.