trans-Crotonyl chloride → (4S)-3-[(2E)-But-2-enoyl]-4-phenyl-1,3-oxazolidin-2-one

To a stirred solution of (4S)-4-phenyl-1,3-oxazolidin-2-one (12 g, 73.5 mmol) in THF (200 mL) was added n-BuLi (2.5 M, 29.4 mL, 73.5 mmol) dropwise via a syringe at −78° C. The resulting reaction mixture was stirred at −78° C. for 5 minutes before (2E)-but-2-enoyl chloride (8.46 mL, 88.0 mmol) was added dropwise via a syringe. The reaction mixture was allowed to warm to ambient temperature and was quenched by addition of brine (100 mL) and water (100 mL). A mixture of ethyl acetate and hexanes (1:2, 100 mL) was added to partition the mixture and the organics were separated, dried over sodium sulfate, filtered and concentrated. The resultant oil was recrystallized in 5% ethyl acetate in hexanes (after seeding with crystals obtained from earlier batches) to yield (4S)-3-[(2E)-but-2-enoyl]-4-phenyl-1,3-oxazolidin-2-one (15.7 g, 67.9 mmol). 1H NMR (500 MHz, CDCl3) δ7.4 (m, 6H), 5.5 (m, 1H) 4.73 (t, J=8.8 Hz, 1H), 4.30 (m, 1H), 1.97 (dd, J=6.8, 1.5 Hz, 3H).

1. customThe resulting reaction mixture
2. additionwas added dropwise via a syringe
3. customwas quenched by addition of brine (100 mL) and water (100 mL)
4. additionA mixture of ethyl acetate and hexanes (1:2, 100 mL)
5. additionwas added
6. customto partition the mixture
7. customthe organics were separated
8. dry with materialdried over sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated
11. customThe resultant oil was recrystallized in 5% ethyl acetate in hexanes (after seeding with crystals obtained from earlier batches)

ORD record

ord-b75a73b847fd483fa7124086599c63df

Source dataset

uspto-grants-2016_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09346825B2