Synthesis of Sulfone Methylene-Substituted Indolines by Radical Cascade Cyclization of 2-Alkynylaniline Derivatives
Ning Ma1, Yuting Leng1, Kaixia Sui1
1College of Chemistry, Henan Key Laboratory of Chemical Biology and Organic Chemistry, State Key Laboratory of Coking Coal Resources Green Exploitation, Zhengzhou University, Zhengzhou 450052, P. R China.
Abstract:
A radical cascade cyclization of 2-alkynylaniline derivatives with sulfonyl chlorides was developed to construct C3-sulfone methylene-substituted indolines in yields of 21 to 85% with a broad substrate scope under metal- and base-free conditions. This protocol could simultaneously build three new chemical bonds and employ a solvent-radical relay strategy, providing a rapid and concise approach toward an indoline framework. Scale-up reactions of this method and further transformations to afford useful indolines were also demonstrated.
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