Triethylamine → Ethyl acetate hexane

Participants

Reaction Conditions

Reaction Steps

A solution of 2-(3-fluoro-4-(trifluoromethyl)phenyl)acetic acid (5.0 g, 22.5 mmol) dissolved in ether (100 mL) was cooled to 0° C. and then treated with triethylamine (3.3 mL, 23.7 mmol) and pivaloyl chloride (2.9 mL, 23.5 mmol). The resulting solution was stirred at 0° C. for 1 hour and then cooled to −78° C. Meanwhile, a solution of (R)-4-benzyloxazolidin-2-one (3.99 g, 22.5 mmol) dissolved in THF (100 mL) was cooled to −78° C. and treated slowly with butyl lithium (12 mL, 25.2 mmol). The resulting solution was stirred at −78° C. for 15 minutes, and then added via cannula into the solution of the mixed anhydride. The mixture was stirred at −78° C. for 15 minutes and then warmed to 0° C. for 30 minutes. Saturated NH4Cl (50 mL) was added to quench the reaction. The reaction was concentrated in vacuo, and the residue was extracted with ethyl acetate (3×150 mL). The organic phase was dried over Na2SO4 and concentrated. The residue was purified by column chromatography, eluting with hexane/ethyl acetate (4:1), (4.9 g, 57.1% yield). 1H NMR (CDCl3, 400 MHz) δ 7.59 (t, J=8.2, 1H), 7.34-7.12 (m, 7H), 4.74-4.66 (m, 1H), 4.39 (d, J=16, 1H), 4.29 (d, J=16, 1H), 4.27-4.19 (m, 2H), 3.27 (dd, 1H), 2.78 (dd, 1H).

Provenance & Evidence