Fu D, Xu J. Tf
2O/2-Chloropyridine-Triggered Synthesis of Benzo[
b]thiophene 1,1-Dioxides from Sulfonium α-Acyl Sulfonylmethylides.
J Org Chem 2024;
89:3072-3083. [PMID:
38357895 DOI:
10.1021/acs.joc.3c02540]
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Abstract
Triflic anhydride and 2-chloropyridine-comediated tandem activation, intramolecular aromatic electrophilic addition, and 1,2-sulfonyl shift via spirocyclic intermediates of sulfonium α-acyl sulfonylmethylides realize the efficient synthesis of 2-alkyl/arylthiobenzo[b]thiophene 1,1-dioxides. The deactivated sulfonyl group determines the site-selectivity of the electrophilic addition via the ipso-attack, while the following S-migration controls the regioselectivity. Some of 2-methylthiobenzo[b]thiophene 1,1-dioxides show fluorescence properties in the solid state and in their solutions.
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