2,2,2-Trifluoroethanol → 3-(2,2,2-Trifluoroethoxy)phenoxathiin 10,10-dioxide

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Reaction Steps

3-Fluorophenoxathiin 10,10-dioxide (Example 47) (6.27 g, 0.025 mmol) was added to a stirred solution prepared from 1,1,1-trifluoro-2-ethanol (Aldrich) (2.64 g, 0.0264 mole), potassium tert-butoxide (Janssen) (2.96 g, 0.0264 mole) and dry acetonitrile (170 mL). The mixture was heated at reflux under nitrogen for 1 hour. The reaction was cooled, and the volatiles were removed by spin evaporation in vacuo. The residue was partitioned between dichloromethane (200 mL) and water (100 mL). The layers were separated, and the organic phase was washed with 0.1 N aqueous hydrogen chloride (75 mL), brine (75 mL) and then dried over magnesium sulfate. The dry solution was spin evaporated in vacuo to give a fluffy residue, which was recrystallized from ethanol to give 6.40 g (77% yield) of 3-(2,2,2-trifluoroethoxy)phenoxathiin 10,10-dioxide, m.p. 167-168° C.

Provenance & Evidence