Compound 3a

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Compound data: 1H NMR

Compound data: 13C NMR

Compound data: 19F NMR

Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

General procedure A: A sealed tube with magnetic stir bar was charged with Pd(OAc)2 (10 mol%, 2.2 mg), NBu₄PF₆ (0.05 mol, 19.4 mg), [F⁺]BF₄^- (0.15 mmol, 34.0 mg), C₆F₅CO₂H (0.5 mmol, 106.0 mg), substrate (0.1 mmol), and TDG4 (20 mol%, 3.7 mg) in air. Then, benzene (0.4 mL) or DCM (0.4 mL) was added as solvent. The reaction mixture was stirred at room temperature for 10 minutes, then at 70 ^oC for 24 hours. Upon completion, the reaction mixture was cooled to room temperature, diluted with ethyl acetate, filtered through a silica plug, and concentrated in vacuo. The crude reaction mixture was purified on silica gel using hexanes/ethyl acetate as eluent to afford the desired product as a mixture with the corresponding substrate. Isolated yield were calculated based on the isolated mass and the ratio of substrate and product determined by analysis of ¹H NMR spectrum. Pure analytical samples for characterization were isolated by multiple preparative TLC.

1a was fluorinated following general procedure A described above, using benzene as solvent. Due to the volatility of the product, the yield was determined by ¹H NMR analysis of the crude product using CH₂Br₂ (0.2 mmol, 14 uL) as the internal standard (61% NMR yield of 3a). Pure analytical sample was isolated by preparative TLC using hexanes/THF as eluent. ¹H NMR (600 MHz, CDCl₃): δ 10.16 (s, 1H), 8.09 (s, 1H), 7.91 (d, J = 8.2 Hz, 1H), 7.88 (d, J = 8.2 Hz, 1H), 6.48 (dq, J = 48.4, 6.3 Hz, 1H), 1.65 (dd, J = 24.1, 6.3 Hz, 3H). ¹³C NMR (150 MHz, CDCl₃): δ 191.37, 147.99 (d, J = 21.0 Hz), 132.06 (d, J = 3.8 Hz), 130.84 (q, J = 23.7 Hz), 130.69 – 130.76 (m), 130.61 – 130.69 (m), 126.35 (d, J = 14.2 Hz), 123.36 (q, J = 272.3 Hz), 87.84 (d, J = 169.8 Hz), 23.18 (d, J = 24.6 Hz). ¹⁹F NMR (376 MHz, CDCl₃): δ –63.18, –174.95. HRMS (ESI-TOF): m/z calculated for C₁₀H₇F₄O^- [M-H]^- 219.0439, found 219.0448.