Diisopropylethylamine → (S)-tert-butyl 5-((S)-2-((R)-4-benzyl-2-oxooxazolidin-3-yl)-1-(3-chlorophenyl)-2-oxoethyl)-2,2-dimethylpyrrolidine-1-carboxylate

Temperature

-78 °C

A solution of (R)-4-benzyl-3-(2-(3-chlorophenyl)acetyl)oxazolidin-2-one (0.975 g, 2.96 mmol) in dry DCM (125 mL) was cooled to −78° C., and TiCl4 (3.10 mL, 3.10 mmol) was added. DIEA (0.566 mL, 3.25 mmol) was added to this stirring cold solution for 15 minutes. A solution of tert-butyl 5-methoxy-2,2-dimethylpyrrolidine-1-carboxylate (0.881 g, 3.84 mmol) in DCM (20 mL) was added to the cold mixture. The reaction was stirred for 15 minutes at −78° C. and then warmed to −10° C. (ice/acetone) and stirred for 3 hours. The reaction was quenched with NH4Cl, diluted with DCM (50 mL), water (50 mL), and the layers were separated. The aqueous layer was extracted with DCM (25 mL), dried (MgSO4) and concentrated to an oil. TLC (10% ethyl acetate/hexanes) shows desired product at Rf˜0.2. Purification by flash chromatography (5% ethyl acetate/hexanes-10% ethyl acetate/hexanes) gave (S)-tert-butyl 5-((S)-2-((R)-4-benzyl-2-oxooxazolidin-3-yl)-1-(3-chlorophenyl)-2-oxoethyl)-2,2-dimethylpyrrolidine-1-carboxylate (0.98 g, 1.86 mmol, 62.9% yield). HPLC, 254 nm, 100% purity, retention time=3.86 minutes.

1. stirringstirred for 3 hours
2. customThe reaction was quenched with NH4Cl
3. additiondiluted with DCM (50 mL), water (50 mL)
4. customthe layers were separated
5. extractionThe aqueous layer was extracted with DCM (25 mL)
6. dry with materialdried (MgSO4)
7. concentrationconcentrated to an oil
8. customPurification by flash chromatography (5% ethyl acetate/hexanes-10% ethyl acetate/hexanes)

ORD record

ord-1ba79c457c584f99a0509362407999ed

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08618097B2