Brønsted-Acid-Promoted Selective C2–N1 Ring-Expansion Reaction of Indoles toward Cyclopenta[<i>b</i>]quinolines
Yajie Yang, Yilin Zhu, Liqiang Yin, Lu Cheng, Chengyu Wang, Yanzhong Li
Abstract
A novel Brønsted-acid-promoted selective C2-N1 ring-expansion reaction of indoles has been developed that provides a rapid and efficient protocol for the preparation of fused quinolines. A variety of corresponding quinolines were obtained in high yields. Controlled experiments revealed that C2-spiroindolenines might be intermediates of this C2-N1 ring-expansion reaction. The notable advantages of this process include excellent yields, good functional group tolerance, and operational simplicity.
Topics & Concepts
ChemistryRing (chemistry)Brønsted–Lowry acid–base theoryCombinatorial chemistryReaction conditionsMedicinal chemistryCatalysisStereochemistryOrganic chemistryCatalytic C–H Functionalization MethodsAsymmetric Synthesis and CatalysisOxidative Organic Chemistry Reactions