Hydrogen Peroxide → (R)-2-(3-Chloro-4-(methylsulfonyl)phenyl)-3-cyclopentylpropanoic acid

Participants

Reaction Steps

A solution of lithium hydroxide (215 mg, 9.0 mmol) in water (2.8 mL) was treated with a 30% aqueous hydrogen peroxide solution (2.0 mL, 18 mmol). This freshly prepared lithium hydroperoxide solution was then cooled to 0° C. and then slowly added to a cooled (0° C.) solution of 4(R)-benzyl-3-[2(R)-(3-chloro-4-methanesulfonyl-phenyl)-3-cyclopentyl-propionyl]-oxazolidin-2-one (2.20 g, 4.5 mmol) in tetrahydrofuran (18 mL) and water (5.8 mL). After 1.5 h at 0° C., the reaction was quenched with a 1.5N aqueous sodium sulfite solution (25 mL) and was diluted with water (150 mL). The aqueous layer was extracted with diethyl ether (3×50 mL). The aqueous layer was then acidified with a 1N aqueous hydrochloric acid solution to pH=2 and extracted with ethyl acetate (3×50 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230–400 mesh, 75/25 hexanes/ethyl acetate with 1% acetic acid) afforded 2(R)-(3-chloro-4-methanesulfonyl-phenyl)-3-cyclopentyl-propionic acid (1.26 g, 85%) as a white solid: mp 106.1–108.8° C.; [α]23589=−43.0° (c=0.172, chloroform); EI-HRMS m/e calcd for C15H19ClO4S (M+) 330.0692, found 330.0690.

Provenance & Evidence