Direct Photoexcitation of Xanthate Anions for Deoxygenative Alkenylation of Alcohols
Hong-Mei Guo, Bin-Qing He and Xuesong Wu*
*School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China,
Email: xswuhust.edu.cn
H.-M. Guo, B.-Q. He, X. Wu, Org. Lett., 2022, 24, 3199-3204.
DOI: 10.1021/acs.orglett.2c00889
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Abstract
Xanthate salts are a unique class of visible-light-excitable alkyl radical precursors that act simultaneously as strong photoreductants and alkyl radical sources. Upon direct photoexcitation of xanthate anions, efficient deoxygenative alkenylation and alkylation of a wide range of primary, secondary, and tertiary alcohols have been achieved avoiding any photocatalysts.
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proposed mechanism
Details
This study explores the use of xanthate salts as visible-light-excitable alkyl radical precursors for the deoxygenative alkenylation and alkylation of alcohols. The method avoids the need for photocatalysts, utilizing the strong photoreductant properties of xanthate anions upon direct visible-light excitation. This approach enables efficient transformations of primary, secondary, and tertiary alcohols via a one-pot protocol, demonstrating broad substrate scope and good functional group tolerance. The process involves the formation of xanthate salts from alcohols, which upon photoexcitation, generate alkyl radicals through single-electron transfer (SET) processes. The study highlights the potential of this method for late-stage functionalization of complex molecules, offering a cost-effective and practical alternative to traditional photoredox catalysis. The research also delves into the mechanistic aspects, proposing pathways for the radical processes involved. The findings suggest that xanthate salts can serve as a versatile platform for various radical transformations, paving the way for further synthetic applications in organic chemistry.
Key Words
alkenes, photochemistry
ID: J54-Y2022