The 2,4-dimethyl-7-pentafluorosulfanyl-5-(trifluoromethyl)dibenzo[b,d]thiophenium trifluoromethanesulfonate: The SF5-analog of Umemoto salt

• The SF5-analog of Umemoto salt was prepared in just two steps.
• The methodology illustrates the potential utility of 4-(pentafluorosulfanyl)benzenediazonium tetrafluoroborate as building block for SF5-aromatics.
• Trifluoromethylating ability of the SF5-derivative of Umemoto salt toward reactive aromatics was surveyed.

The SF5-analog of the Umemoto salt was synthesized in just two steps by combining our recently reported SF5-biaryl synthesis, via Suzuki coupling with 4-(pentafluorosulfanyl)benzenediazonium tetrafluoroborate, with Magnier's one-pot synthesis of dibenzothiophenium salts employing CF3SO2Na and triflic anhydride. The trifluoromethylating power of this novel onium salt toward reactive arenes was tested in a survey study on small scale.

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