GENERAL METHOD: To a solution of dichloroethane (2 mL) containing IF5-pyridine-HF (321 mg, 1.0 mmol), Et3N-6HF (553 mg, 2.5 mmol) and 2a (113 mg, 0.5 mmol) were sequentially added at room temperature. The reaction mixture was stirred at 60 °C for 9 hours. Upon completion of the reaction, the dark red solution was poured into water (20 mL) and extracted with dichloromethane (20 mL x 3). The organic layers were combined, washed sequentially with aqueous NaHCO3 and aqueous Na2S2O3, and dried over MgSO4. The yield of 4a was determined to be 74% by 19F NMR using fluorobenzene as an internal standard. Purification by column chromatography (silica gel/hexane) afforded 4a. IR (pure) 2963, 1256, 1212 cm-1; 1H NMR δ 7.23 (d, J = 8.8 Hz, 2H), 7.13 (d, J = 8.4 Hz, 2H), 2.95-2.85 (m, 1H), 1.24 (d, J = 6.8 Hz, 6H); 19F NMR δ -58.53 (s, 3F); 13C NMR δ 147.7, 147.3, 127.8 (2C), 121.0 (2C), 120.7 (q, 1JC-F = 257.7 Hz), 33.7, 24.1 (2C); HRMS (EI) calculated value C10H11F3O 204.07620, measured value 204.07606.
