O-Xylene → (3,4-Dimethylphenyl)(fluoromethyl)(phenyl)sulfonium tetrafluoroborate

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Reaction Steps

Monofluoromethyl phenyl sulfoxide (645 mg, 4.08 mmol) of example 2 was dissolved in dry diethyl ether (15 ml) under argon atmosphere. O-xylene (0.54 ml, 1.1 eq) was added to the previous solution and then the mixture was cooled to a temperature below −50° C. After stabilizing the temperature, trifluoromethanesulfonic anhydride (0.68 mL, 1.0 eq) was added slowly maintaining the same temperature. The mixture was stirred until the reaction was complete. HBF4 solution (54%, 1.12 mL, 2 eq) was added and the resulting suspension was stirred for 30 minutes. The precipitate tetrafluoroborate salt was isolated by filtration, washed with diethyl ether at 0° C. and dried. The desired product was obtained as a slightly yellow oily solid (1.729 g).

Provenance & Evidence