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Photoredox-Enabled Difluoromethylation Cyclization and Quinoxalin-2(1H)-one Integration: Access to
Dulin Kong1, Lianglong Sun2, Qinghao Dong2
1Engineering Research Center of Tropical Medicine Innovation and Transformation of Ministry of Education, Hainan Provincial Key Laboratory of Research and Development on Tropical Herbs, School of Pharmaceutical Sciences, Hainan Medical University, Haikou571199, China.
Abstract:
Herein, a novel protocol for the photoredox-enabled intramolecular difluoromethylation cyclization and intermolecular domino quinoxalin-2(1H)-one integration is established. This version allows facile access to structurally diverse gem-difluoro-quinolines. A wide substrate scope, wide functional group compatibility, bioactive molecule decoration, and gram-scale amplification attest to the utility of this protocol. A radical cyclization mechanism is proposed on the basis of radical inhibition experiments, a visible-light irradiation on-off test, AQE calculations, and Stern-Volmer fluorescence quenching experiments.
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