Cesium carbonate → Benzoic acid, 2-bromo-4-ethenyl-, ethyl ester

Participants

Reaction Steps

To a stirred solution of ethyl 2-bromo-4-iodobenzoate (5 g, 14.3 mmol) in THF/water (100 mL, 9:1) was added potassium vinyltrifluoroborate (1.89 g, 14.3 mmol), Cs2CO3 (18.27 g, 56.07 mmol) and triphenylphosphine (0.22 g, 0.85 mmol) and the reaction mixture was degassed with argon for 20 min, then charged with PdCl2 (0.05 g, 0.28 mmol). The reaction mixture was heated to reflux for 16 h. The reaction mixture was cooled to ambient temperature and filtered through a celite bed and washed with ethyl acetate. The filtrate was again extracted with ethyl acetate and the combined organic layers washed with water and brine, dried over Na2SO4 and concentrated under reduced pressure to afford crude compound. The crude compound was purified by column chromatography (SiO2, 100-200 mesh; eluting with 2% ethyl acetate/petroleum ether) to afford the title compound as a light brown gummy material (2 g, 56%): 1H NMR (400 MHz, CDCl3) δ 7.78 (d, J=8.4 Hz, 1H), 7.71 (d, J=1.2 Hz, 1H), 7.51 (d, J=8.4 Hz, 1H), 6.69 (dd, J=17.6, 10.8 Hz, 1H), 5.86 (d, J=17.6 Hz, 1H), 5.42 (d, J=11.2 Hz, 1H), 4.42 (q, J=7.2 Hz, 2H), 1.43 (t, J=3.6 Hz, 3H); ESIMS m/z 255.18 ([M+H]+); IR (thin film) 1729 cm−1.

Provenance & Evidence