N-bromobutanimide → (4R)-4-benzyl-3-[(2R)-2-bromo-3-butylheptanoyl]-1,3-oxazolidin-2-one

Temperature

-40 °C

A slurry of copper bromide (I) dimethyl sulfide complex (5.132 g, 24.967 mmol) in THF (60 mL) and dimethyl sulfide (30 mL) as a co-solvent was cooled to −40° C. and n-butyl magnesium chloride (25 mL, 49.93 mmol) was added dropwise for 10 min and stirred for 20 min while warning to −15° C. The black slurry was cooled to −40° C. and (4R)-4-benzyl-3-[(E)-2-heptenoyl]-1,3-oxazolidin-2-one (6 g, 20.80 mmol) was added dropwise over 10 min as a solution in THF (20 mL) at −40° C. The reaction was let warm up to 25° C. overnight (20 h). N-Bromosuccinimide (7.407 g, 41.61 mmol) was added portionwise to a cold −78° C. solution of the black slurry. It was allowed to warm to 0° C. and was stirred for an additional 3 h. The reaction was quenched with a 1:1 solution of saturated ammonium carbonate and 0.5 N potassium bisulfate. The black slurry became greenish to blue. A precipitate formed (light blue). It was filtered. The mother liquor was diluted with ethyl acetate (150 mL) and the organic was dried over MgSO4, filtered, concentrated to obtain (4R)-4-benzyl-3-[(2R)-2-bromo-3-butylheptanoyl]-1,3-oxazolidin-2-one as a crude semi-solid (green) (8.49 g, 96.15%). Mass Spectrum (−ESI): 423 (M−H)−.

1. customwhile warning to −15° C
2. temperatureThe reaction was let warm up to 25° C. overnight (20 h)
3. temperatureto warm to 0° C.
4. stirringwas stirred for an additional 3 h
5. customThe reaction was quenched with a 1:1 solution of saturated ammonium carbonate and 0.5 N potassium bisulfate
6. customA precipitate formed (light blue)
7. filtrationIt was filtered
8. additionThe mother liquor was diluted with ethyl acetate (150 mL)
9. dry with materialthe organic was dried over MgSO4
10. filtrationfiltered
11. concentrationconcentrated

ORD record

ord-b6c9f9880d6c4aca8e0aadd54a9ad1ec

Source dataset

uspto-grants-2003_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06610734B2