Trifluoroacetic acid → 2-Benzyl-5-bromo-4-methoxyphenol

Participants

Reaction Steps

To a solution of (4-bromo-2-hydroxy-5-methoxyphenyl)(phenyl)methanone (100 mg, 0.325 mmol) in 0.22 mL of anhydrous DCM (C=1.5M), were successively added dropwise trifluoroacetic acid (0.25 mL, 10 eq) and triethylsilane (0.21 mL, 4 eq). After 17 h of stirring at r.t., the reaction mixture was hydrolyzed with a saturated NH4Cl solution (5 mL) The layers were diluted with 20 mL of DCM and 20 mL of water and then separated. The aqueous layer was extracted twice with DCM (2×5 mL). The combined organic phase was washed twice with a saturated NaHCO3 solution (2×20 mL), brine (20 mL), dried over MgSO4, filtered and concentrated in vacuo. The crude product was purified by silica gel flash chromatography (Cyclohexane/AcOEt 97:3) to afford the desired product in 72% yield (68.5 mg) as an uncoloured oil. 1H NMR (300 MHz, CDCl3) δ 7.36-7.28 (m, 2H), 7.28-7.20 (m, 3H), 7.01 (s, 1H), 6.70 (s, 1H), 4.89 (s, 1H), 3.96 (s, 2H), 3.80 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 150.3 (C), 148.1 (C), 139.4 (C), 128.8 (CH), 128.7 (CH), 127.5 (C), 126.6 (CH), 120.7 (CH), 115.0 (CH), 109.4 (C), 57.0 (OCH3), 36.4 (CH2Bn); MS (ESI) m/z: 310.1, 312.1 [M+NH4, 79Br, 81Br]+; 602.0, 604.3, 606.1 [2M+NH4, 79Br, 81Br]+.

Provenance & Evidence