Visible Light-Induced Umpolung Synthesis of 3, 3-Disubstituted Oxindoles via the Substrate-Photosensitive Strategy
Jingjing Yang , Tingting Wang , Benhui Sui , Hongyu Wang , Bo Tang
Chinese Journal of Chemistry ›› 2025, Vol. 43 ›› Issue (4) : 431 -436.
Visible Light-Induced Umpolung Synthesis of 3, 3-Disubstituted Oxindoles via the Substrate-Photosensitive Strategy
3, 3-Disubstituted oxindoles, forming the core of extensive bioactive natural products and drugs, attract tremendous efforts to develop efficient methods for their preparation. Here, a photocatalyst-free approach for the synthesis of 3, 3-disubstituted oxindoles via a substrate-photosensitive strategy under visible light was successfully developed. Preliminary mechanistic studies illustrated that isatin-derived imines can be directly excited by visible light to generate strong oxidant states, facilitating subsequent single-electron transfer (SET) processes with Hantzsch esters to afford the corresponding α-amino radical intermediates. Thus, these α-amino radicals promote the subsequent Giese radical addition or radical/radical cross-coupling reactions to furnish diverse functionalized 3-substituted 3-aminooxindoles in high yields.
Umpolung synthesis / Photocatalysis / α-Amino radical / Isatin-derived imines / 3-Substituted 3-aminooxindoles
2024 SIOC, CAS, Shanghai, & WILEY-VCH GmbH
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