Photocatalytic Markovnikov-Selective Sulfonation of Alkynes for Indoline Synthesis
Yu-Wen Huang1, Jin-Lian Bai1, Dong Yu1
1Jiangsu Provincial University Key Laboratory of Green Biomanufacturing for Pharmaceuticals, School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing 211816, P. R. China.
Abstract:
The indoline scaffold, a privileged class of nitrogen-containing heterocycles, is ubiquitous in bioactive natural products and pharmaceuticals; consequently, the development of efficient synthetic strategies remains a forefront of organic synthesis. Herein, we report a visible-light-induced Markovnikov-selective sulfonylation/cyclization cascade, enabling the mild and efficient construction of 3-sulfonyl indolines from o-aminoarylalkynes and sodium sulfinates. Mechanistic studies reveal that the transformation proceeds via a radical-mediated pathway, initiated through either an electron donor-acceptor (EDA) complex or a photocatalytic cycle, wherein sodium sulfinate serves as a pivotal electron donor. This work provides a green and atom-economical strategy for the modular synthesis of functionalized indolines.
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