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Synfacts 2010(4): 0402-0402
DOI: 10.1055/s-0029-1219497
DOI: 10.1055/s-0029-1219497
Synthesis of Heterocycles
© Georg Thieme Verlag
Stuttgart ˙ New York
Synthesis of Thiophenium Salts: A Trifluoromethylation Reagent
A. Matsnev, S. Noritake, Y. Nomura, E. Tokunaga, S. Nakamura, N. Shibata*
Nagoya Institute of Technology, Japan
Further Information
Publication History
Publication Date:
22 March 2010 (online)
Significance
A triflic acid catalyzed intramolecular cyclization of ortho-ethynylaryltrifluoromethylsulfanes to S-(trifluoromethyl)thiophenium salts (Yagupolskii-Umemoto-type reagent) is reported. Simple catalysts, such as AuCl3 and CuCl2 for the cyclization of ortho-thiosubstituted aryl alkynes to benzothiophenes (I. Nakamura, T. Sato, Y. Yamamoto Angew. Chem. Int. Ed. 2006, 45, 4473), are not suitable in this reaction. Among the Brønsted acids tested, TfOH was found to be the only efficient acid in affording the desired products.