Exploiting the Distal Reactivity of Indolyl Methylenemalononitriles: An Asymmetric Organocatalyzed [4+2] Cycloaddition with Enals Enables the Assembly of Elusive Dihydrocarbazoles
作者:Gloria Rassu、Claudio Curti、Vincenzo Zambrano、Luigi Pinna、Nicoletta Brindani、Giorgio Pelosi、Franca Zanardi
DOI:10.1002/chem.201602793
日期:2016.8.26
generation of indolyl ortho‐quinodimethanes from 2‐methylindole‐based methylenemalononitriles by amine‐mediated remote C(sp3)−H deprotonation was developed. These intermediates were efficiently trapped by diverse enals to provide a rapid entry to 2,9‐dihydro‐1H‐carbazole‐3‐carboxyaldehyde structures through a formal asymmetric [4+2] eliminative cycloaddition governed by a α,α‐diphenylprolinol trimethylsilyl
通过胺介导的远程C(sp 3)-H去质子化作用,从2-甲基吲哚基的亚甲基丙二腈原位生成吲哚基邻喹啉甲烷的空前技术得到了发展。这些中间体被各种烯类有效地捕获,可以通过由α,α-二苯基脯氨醇三甲基甲硅烷基醚控制的形式不对称[4 + 2]消除环加成反应,快速进入2,9-二氢-1 H-咔唑-3-羧醛结构催化剂。