Fluorination of methyl arenedithiocarboxylates

To a dichluromethane (1.5 ml) solution of ArCS2Me (0.5 mmol) and tetra-n-butylammonium dihydrogentrifluoride (1.5 mmol) was added DBH (2 mmol) in one poition at 0°C, and the resulting mixture was stirred for 1 h at room temperature, then poured into an aqueous solution of NaHCO, and NaHS03, and extracted with diethyl ether. The ethereal layer was dried (Na2S04), filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to afford the trifluoromethyl-substituted aromatic 

The commercially available dicthylaminosulfur trifluoride, Et3NSF, (DAST), was shown to be a particularly convenient fluorination reagent (for a review, see (259]). The sequence shown here was used for the preparation of a,a-difluoroethers [138], 

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