Lithium Hexamethyldisilazide → (4R,5S)-3-((R)-3-cyclopentyl-2-phenyl-propionyl)-4-methyl-5-phenyl-oxazolidin-2-one

Participants

Reaction Conditions

Reaction Steps

The title A compound, (4R,5S)-4-methyl-5-phenyl-3-phenylacetyl-oxazolidin-2-one (5.00 g, 16.93 mmol) is dissolved in anhydrous THF (50 mL) and cooled to −78° C. Lithium bis(trimethylsilyl)amide (1 M in THF, 16.93 mL, 16.93 mmol) is added dropwise over 10 min. To this is added a solution of the title B compound, trifluoromethanesulfonic acid cyclopentylmethyl ester (3.93 g, 16.93 mmol) in anhydrous THF (15 mL). The reaction is stirred at −78° C. for 10 min, then the cold bath is removed. The reaction is allowed to stir and warm to RT. After one hour, the reaction is concentrated to remove the solvent, resulting in a yellow oil. This is dissolved in ethyl acetate (300 mL) and washed with water (2×200 mL). The organic solution is dried over anhydrous sodium sulfate, filtered, and concentrated to a yellow oil. This is recrystallized from hexanes to afford (4R,5S)-3-((R)-3-cyclopentyl-2-phenyl-propionyl)-4-methyl-5-phenyl-oxazolidin-2-one as a white solid: 1H NMR (400 MHz, DMSO-D6) 0.8 (d, J=6.6 Hz, 3 H) 1.1 (d, J=16.2 Hz, 2 H) 1.4 (m, 2 H) 1.5 (d, J=5.8 Hz, 2 H) 1.6 (s, 2 H) 1.8 (d, J=7.1 Hz, 2 H) 2.0 (d, J=13.4 Hz, 1 H) 4.8 (s, 1 H) 5.1 (s, 1 H) 5.7 (d, J=7.1 Hz, 1 H) 7.3 (s, 1 H) 7.4 (m, 9 H); LC/MS 378.2 (M+1).

Provenance & Evidence