General procedure for the synthesis of compounds 2, 4, and 6 (taking 2a as an example): To a 15

mL dried pressure tube were added 1a (98 mg, 0.5 mmol), n-Bu4NBr (16 mg, 0.05 mmol),

TMSCF2Br (152 mg, 0.75 mmol), and 2 mL of toluene in sequence at room temperature. The tube

was sealed by a rubber septum tightly and the reaction mixture was stirred at 110 °C for 2 h. Then,

the additional TMSCF2Br, which was pre-dissolved in 0.5 mL of toluene (101 mg, 0.5 mmol), was

injected by a syringe to the mixture followed by reacting another 4 h. After the reaction mixture was

cooled to room temperature, a solution of n-Bu4NF in THF (0.1 mL, M = 1 mol/L, 0.1 mmol) was

injected and the reaction continued to be stirred at room temperature for 3 h. The resulting mixture

was then poured into ice water (30 mL), extracted with CH2Cl2 (3 × 15 mL). The organic layers

were combined and dried over anhydrous MgSO4. After removal of the solvents in vacuo, the

residue was subjected to column chromatography (silica gel; petroleum ether/ethyl acetate: 100/1,

v/v) to give 2a (111 mg, 98%) as a white solid.

1-(Biphenyl-4-yl)-2-fluoroprop-2-en-1-one (2a)

 

S2

 

White solid. mp: 56-58 ℃. ¹H NMR (500 MHz, CDCl3) δ 5.50 (dd, J = 3.5 Hz, J = 15.0 Hz, 1H),

5.61 (dd, J = 3.5 Hz, J = 45.5 Hz, 1H), 7.41 (t, J = 7.5 Hz, 1H), 7.48 (t, J = 7.5 Hz, 2H), 7.63 (d, J =

7.5 Hz, 2H), 7.70 (d, J = 8.5 Hz, 2H), 7.97 (d, J = 7.5 Hz, 2H). 13C NMR (125 MHz, CDCl3) δ

104.0 (d, J = 16.3 Hz, 1C), 127.1 (2C), 127.3 (2C), 128.4, 129.0 (2C), 130.1 (d, J = 5.0 Hz, 2C),

134.1, 139.7, 146.2, 160.0 (d, J = 267 Hz, 1C), 186.7 (d, J = 29.4 Hz, 1C). 19F NMR (470 MHz,

CDCl3) δ -112.5 (dd, J = 15.0 Hz, J = 45.6 Hz, 1F). HRMS (ESI-TOF) calcd for C15H12FO+

([M+H]+) 227.0867, found 227.0865.

1-(4-Tert-butylphenyl)-2-fluoroprop-2-en-1-one (2b)

 

Light yellow oil. ¹H NMR (500 MHz, CDCl3) δ 1.35 (s, 9H), 5.47 (dd, J = 3.5 Hz, J = 15.5 Hz, 1H),

5.56 (dd, J = 3.5 Hz, J = 45.5 Hz, 1H), 7.49 (d, J = 8.5 Hz, 2H), 7.83 (d, J = 8.5 Hz, 2H). 13C NMR