Organic Letters
Letter
Scheme 5. Proposed Mechanism
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diphenylethane 6. The generation mechanism of byproduct was
also proposed. If no Na2SO3 is added to the reaction, the benzyl
radical will probably be oxidized to a benzyl cation. The benzyl
cation can be attacked by 1n to produce the cation intermediate
C, and subsequent intramolecular nucleophilic attack generates
the cation intermediate D. Finally, the nucleophilic attack by Br−
produces benzyl bromide and byproduct 5.
In summary, we have successfully constructed 2-CF2/CF3-
containing benzothiazoles through a visible-light-induced
radical cascade cyclization process. In contrast with the
traditional use of tertiary amine as reductant to achieve SET
processes in photocatalytic reactions,11 we use the inorganic salt
sodium sulfite as a reductant to play the same role and improve
the efficiency of the reaction.
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ASSOCIATED CONTENT
* Supporting Information
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(14) Prier, C. K.; Rankic, D. A.; MacMillan, D. W. C. Chem. Rev. 2013,
113, 5322−5363.
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The Supporting Information is available free of charge on the
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Preparation of substrates, general procedure, character-
ization data, 1H and 13C NMR spectra (PDF)
AUTHOR INFORMATION
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Corresponding Author
ORCID
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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The authors acknowledge the financial support provided by the
National Natural Science Foundation of China. We also express
gratitude for the support and valuable suggestions from the
Instrumental Analysis Center of Shanghai Jiao Tong University.
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