Hydrochloric Acid → (4S)-4-benzyl-3-[(5S)-5-{[tert-butyl(dimethyl)silyl]oxy}-5-(4-fluorophenyl)pentanoyl]-1,3-oxazolidin-2-one

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Reaction Steps

(4S)-4-Benzyl-3-[(5S)-5-(4-fluorophenyl)-5-hydroxypentanoyl]-1,3-oxazolidin-2-one (37.54 mmol) was dissolved in N,N-dimethylformamide (40 mL) and then imidazole (2.97 g, 43.6 mmol) and tert-butyldimethylsilyl chloride (6.12 g, 40.6 mmol) were added. The reaction was stirred at room temperature for 19 h, poured into 0.1 N hydrochloric acid (500 mL) and extracted with 1:1 ethyl acetate-hexane (500 mL). The organic layer was washed with water (2×500 mL), brine (300 mL), dried over sodium sulfate, filtered, and concentrated. The residue was purified by crystallization from methanol (55 mL) by heating to a light boil and cooling slowly to room temperature over 18 h. The crystals were filtered cold and washed with cold methanol (45 mL) to afford (4S)-4-benzyl-3-[(5S)-5-{[tert-butyl(dimethyl)silyl]oxy}-5-(4-fluorophenyl)pentanoyl]-1,3-oxazolidin-2-one (16.04 g, 88% yield) as a white crystalline solid; mp 87.6° C.; Rf 0.66 (1:2 ethyl acetate-hexane); 1H NMR (300 MHz, CDCl3) δ 7.36-7.18 (m, 7H), 6.99 (t, J=8.7 Hz, 2H), 4.69-4.61 (m, 2H), 4.18-4.13 (m, 2H), 3.27 (dd, J=13.5, 3.2 Hz, 1H), 2.96-2.89 (m, 2H), 2.73 (dd, J=13.5, 9.7 Hz, 1H), 1.82-1.63 (m, 4H), 0.88 (s, 9H), 0.04 (s, 3H), −0.15 (s, 3H) ppm; MS [M−OSi(CH3)2C(CH3)3]+354.0.

Provenance & Evidence