Iodine → (6-Fluoro-2-iodo-3-trifluoromethoxy-phenyl)-carbamic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 2 (31.34 g, 117.2 mmol) in THF (180 mL) at −78° C. is added sec-BuLi (1.4 M in cyclohexane, 200 mL, 280 mmol) dropwise over a 1 h period. After 20 min, a solution of I2 (44.6 g, 175.8 mmol) in THF (150 mL) is added dropwise over a 30 min period. This mixture is then stirred at −78° C. for 30 min. Saturated NH4Cl is added, and the cooling bath is removed. The reaction mixture is partitioned between H2O and EtOAc. The two layers are separated, and the organic layer is washed with 10% Na2SO3, H2O, and brine, dried over MgSO4, filtered, and concentrated in vacuo. The residue is suspended in DCM (50 mL), and heptane (300 mL) is added. The white powder 3 (18.1 g, 39%) from the resulting suspension is collected by suction filtration and air-dried. The filtrate is concentrated in vacuo, and the residue is suspended in heptane (200 mL). Another batch of 3 (3.8 g, 8%) is collected by suction filtration and air-dried. Additional product can be obtained by purifying the filtrate via silica gel chromatography. 1H NMR (CDCl3) δ 7.30-17.10 (m, 2H), 6.16 (br s, 1H), 4.26 (q, J=7.1 Hz, 2H), 1.32 (t, J=7.1 Hz, 3H); 19F NMR (CDCl3) δ−56.90 (s, 3F), −114.35 (d, J=8.5 Hz, 1F); MS 394 (M+1, 100%), 374, 364, 321, 267.

Provenance & Evidence