Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China.
J Org Chem. 2012 Nov 2;77(21):9510-20. doi: 10.1021/jo300339a. Epub 2012 Apr 26.
3-Alkenylation or 3-alkylation of indole with propargylic alcohols could be efficiently controlled by the catalyst. In the presence of triflic acid, 3-alkenylation of indole occurred and a 3,4-dihydrocyclopenta[b]indole skeleton was effectively constructed in moderate to excellent yields via a cascade process. In the presence of Cu(OTf)(2), 3-alkylation of indole resulted in the formation of 3-propargylic indole, which could be further converted into 2-iodo-1,4-dihydrocyclopenta[b]indoles in the presence of N-iodosuccinimide and boron trifluoride etherate. Possible mechanisms related to the 3-alkenylation or 3-alkylation of indole and their extension to the formation of 3,4-dihydrocyclopenta[b]indoles or 1,4-dihydrocyclopenta[b]indoles are postulated and discussed.
在催化剂的作用下，吲哚与丙炔醇的 3-烯丙基化或 3-烷基化可以得到有效控制。在三氟甲磺酸存在下，吲哚发生 3-烯丙基化反应，通过级联过程以中等至优异的收率有效地构建了 3,4-二氢环戊[b]吲哚骨架。在 Cu(OTf)(2)存在下，吲哚的 3-烷基化反应生成 3-丙炔基吲哚，在 N-碘代丁二酰亚胺和三氟化硼乙醚的存在下，它可以进一步转化为 2-碘-1,4-二氢环戊[b]吲哚。本文提出并讨论了与吲哚的 3-烯丙基化或 3-烷基化及其扩展到 3,4-二氢环戊[b]吲哚或 1,4-二氢环戊[b]吲哚的形成有关的可能机制。
