[Cl:1][C:2]1[CH:3]=[C:4]([CH2:8][C:9]([OH:11])=O)[CH:5]=[CH:6][CH:7]=1.CCN(C(C)C)C(C)C.CC(C)(C)C(Cl)=O.[CH2:28]([C@@H:35]1[CH2:39][O:38][C:37](=[O:40])[NH:36]1)[C:29]1[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=1.[Li]CCCC.[O-][Mn](=O)(=O)=O.[K+]>C1COCC1>[CH2:28]([C@@H:35]1[CH2:39][O:38][C:37](=[O:40])[N:36]1[C:9](=[O:11])[CH2:8][C:4]1[CH:5]=[CH:6][CH:7]=[C:2]([Cl:1])[CH:3]=1)[C:29]1[CH:30]=[CH:31][CH:32]=[CH:33][CH:34]=1In a 1000 mL flask under N2, 2-(3-chlorophenyl)acetic acid (3.50 g, 20.51 mmol) was added to dry THF (300 mL), and the contents were cooled to 0° C. DIEA (3.93 mL, 22.6 mmol) was added to the stirring solution, followed by portionwise addition of trimethylacetyl chloride (2.60 g, 21.5 mmol). In a separate flask, (R)-4-benzyloxazolidin-2-one (3.82 g, 21.5 mmol) was added to dry THF (75 mL) and cooled to −78° C. under N2. n-BuLi (8.21 mL, 20.5 mmol) was added to this cold stirring solution, and the whole contents were stirred for 30 minutes at −78° C. This solution was then slowly added to the mixed anhydride at 0° C. The reaction was stirred for 2 hours and determined complete by TLC (25% ethyl acetate/hexanes, KMnO4 stain). The reaction was quenched with water (250 mL) and diluted with ethyl acetate (250 mL). The layers were separated, and the organics were washed with brine (100 mL), dried (MgSO4) and concentrated to an oil. The oil was purified by flash chromatography (10% ethyl acetate/hexanes to 25% ethyl acetate/hexanes) to give (R)-4-benzyl-3-(2-(3-chlorophenyl)acetyl)oxazolidin-2-one (1.99 g, 6.03 mmol, 29.4% yield). 1H NMR (400 MHz, CDCl3) 7.37-7.20 (m, 7H), 7.14 (d, J=6.64 Hz, 2H), 4.73-4.64 (m, 1H), 4.28 (dd, J1=16.00 Hz, J2=33.97 Hz, 2H), 4.22-4.16 (m, 2H), 3.27 (dd, J1=3.12 Hz, J2=13.27 Hz, 1H), 2.77 (dd, J1=9.37 Hz, J2=13.27 Hz, 1H).
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