Efficient construction of functionalized pyrroloindolines through cascade radical cyclization/intermolecular coupling
Yonggang Jiang, Dongxiang Liu, Lening Zhang, Cuirong Qin, Hui Li, Hai‐Tao Yang, Patrick J. Walsh, Xiaodong Yang
Abstract
Pyrroloindolines are important structural units in nature and the pharmaceutical industry, however, most approaches to such structures involve transition-metal or photoredox catalysts. Herein, we describe the first tandem SET/radical cyclization/intermolecular coupling between 2-azaallyl anions and indole acetamides. This method enables the transition-metal-free synthesis of C3a-substituted pyrroloindolines under mild and convenient conditions. The synthetic utility of this transformation is demonstrated by the construction of an array of C3a-methylamine pyrroloindolines with good functional group tolerance and yields. Gram-scale sequential one-pot synthesis and hydrolysis reactions demonstrate the potential synthetic utility and scalability of this approach.