Hydrogen Peroxide → (R)-4-(tert-Butoxy)-2-(cyclopentylmethyl)-4-oxobutanoic acid

Participants

Reaction Conditions

Reaction Steps

4-(4-(S)-Benzyl-2-oxo-oxazolidin-3-yl)-3-(R)-cyclopentylmethyl-4-oxo-butyric acid tert-butyl ester (620 mg, 1.49 mmol, 1.0 eq.) was dissolved in THF (35 mL) and cooled in a 0° C. ice-water bath. Hydrogen peroxide (31 w/w %) (654 μL, 5.97 mmol, 4.0 eq.) and LiOH (72 mg, 2.98 mmol, 2.0 eq.) in water (7.5 mL) was added to the reaction mixture. The reaction stirred at 0° C. and judged to completion by LC/MS. Saturated sodium sulfite (18 mL) and sodium bicarbonate (18 mL) is added to the reaction. THF was evaporated by rotary evaporation and extracted the aqueous layer with CH2Cl2 (3×75 mL) to remove the chiral auxiliary. The aqueous layer was acidified at 0° C. with 6M HCl to pH˜1 and extracted with ethyl acetate (4×75 mL). The combined organic extracts were dried over MgSO4, filtered and evaporated to provide 281 mg (1.10 mmol, 73%) of 2-(R)— Cyclopentylmethyl-succinic acid 4-tert-butyl ester as clear oil and used directly in Step B. HPLC-MS calcd. for C14H24O4 (M+Na+) 279.3, found 279.3.

Provenance & Evidence