Phenylacetyl chloride → (4R)-4-Benzyl-3-(phenylacetyl)-1,3-oxazolidin-2-one

Participants

Reaction Steps

To a cold (−78° C.), stirred solution of (4R)-4-benzyl-1,3-oxazolidin-2-one (4.17 g, 23.53 mmol) in THF (100 mL) under nitrogen atmosphere was added n-BuLi (9.5 mL, 23.75 mmol) dropwise via syringe over 10 min. After stirring for 10 min, a solution of 2-phenylacetyl chloride (3.2 mL, 24.20 mmol) in THF (20 mL) was added via cannula over 10 min. After the addition was complete, the reaction mixture was placed in an ice-water bath and was stirred at 0° C. for 1 hr, then removed from the ice bath. To the reaction mixture was added aqueous saturated NH4Cl and was extracted with EtOAc (2×). The combined organics were washed with brine, dried (Na2SO4), filtered and concentrated under reduced pressure. The residue was purified by flash chromatography (Teledyne ISCO CombiFlash Rf, 0% to 100% solvent hexanes/EtOAc, REDISEP® SiO2 120 g). Concentration of appropriate fractions provided Preparation 4E (6.19 g, 89%) as a colorless viscous oil: 1H NMR (400 MHz, CDCl3) δ 7.32-7.39 (4H, m), 7.21-7.32 (4H, m), 7.10-7.17 (2H, m), 4.67 (1H, dddd, J=10.29, 6.34, 3.45, 3.26 Hz), 4.30 (2H, q, J=15.56 Hz), 4.15-4.22 (2H, m), 3.26 (1H, dd, J=13.30, 3.26 Hz), 2.76 (1H, dd).

Provenance & Evidence