Hydrogen Peroxide → (2S)-2-(4-Fluorophenyl)propanoic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of (4S)-3-[(2S)-2-(4-fluorophenyl) propanoyl]-4-isopropyl-1,3-oxazolidin-2-one (2.40 g, 8.60 mmol) in 160 mL THF/H2O (3:1) at 0° C., was added 30% H2O2 (7.8 mL, 68.8 mmol) followed by LiOH (722 mg, 17.2 mmol). The resulting mixture was stirred at 0° C. for 2 h and the excess peroxide was quenched at 0° C. with 1.5 N aqueous Na2SO3 (51 mL). After buffering to pH 9–10 with aqueous NaHCO3 and evaporation of the THF, the oxazolidone chiral auxiliary was recovered by EtOAc extraction (50 mL×3). The aqueous layer was acidified with 3N HCl and extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4, filtered and concentrated in vacuo to give 0.92 g (5.47 mmol, 64%) of (2S)-2-(4-fluorophenyl)propanoic acid; [α]D=+70° (C=1, MeOH): 1H NMR (400 MHz, CDCl3) δ 12.2–11.4 (br, 1 H), 7.31–7.24 (m, 2 H), 7.04–6.97 (m, 2 H), 3.72 (q, 1 H, J=7.3 Hz), 1.49 (d, 3 H, J=7.3 Hz); ESMS m/e: 167.2 (M−H)+.

Provenance & Evidence