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. 2022 Jul 21;12(33):21022-21025.
doi: 10.1039/d2ra04191j.

Metal-free synthesis of C2-quaternary indolinones by (NH4)2S2O8 mediated oxidative dearomatization of indoles

Yu Dong  1 , Jun-Hu Qian  1 , Xiang-Long Chen  1 , Hui Jiang  1 , Xue Li  1 , Qiang Zhou  1 , Ting Mei  1 , Zhi-Chuan Shi  2 , Zhong-Hui Li  1 , Bing He  1
Affiliations

Metal-free synthesis of C2-quaternary indolinones by (NH4)2S2O8 mediated oxidative dearomatization of indoles

Yu Dong et al. RSC Adv. .

Abstract

An efficient metal-free, (NH4)2S2O8 mediated oxidative dearomatization of indoles for the construction of C2-quaternary indolinones was disclosed. A series of C2-quaternary indolinones derivatives with good functional group tolerance were obtained in moderate to excellent yields. This methodology provides an alternative approach for the direct generation of all-carbon quaternary centers at the C2 position of indoles. This catalytic approach represents a step-economic and convenient strategy for the oxidative dearomatization of indoles.

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Conflict of interest statement

There are no conflicts to declare.

Figures

Fig. 1
Fig. 1. Some important bioactive synthetic derivatives with 2,2-disubstituted indolin-3-one structural unit.
Scheme 1
Scheme 1. Previous and present approaches for the synthesis of 2,2-diaryloxindole (R = alkyl or halide group).
Scheme 2
Scheme 2. Plausible reaction mechanism.
See this image and copyright information in PMC

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