Water → HCID 59588960, compound

To a stirred solution of triethyl 2-fluoro-2-phosphonoacetate (0.61 mL, 3 mmol) in dry THF (40 mL) at −10° C. under nitrogen was added n-butyllithium (2.5 M solution in hexanes; 1.16 mL, 2.9 mmol) dropwise. The contents of the vessel were allowed to stir for 5 mins at −10° C. before addition of N-Boc-aminoacetaldehyde (0.378 g, 2.5 mmol, in 5 mL THF). The reaction mixture was then allowed to warm to room temperature and stirred for 16 hours. Water (50 mL) was added to the mixture and the organic layer extracted with diethyl ether (50 mL) and washed with brine (20 mL), dried over MgSO4, filtered and the solvent removed under reduced pressure to afford the crude product as a clear oil (0.850 g). Purification by flash chromatography (silica, ˜4 g) eluting in 5-15% EtOAc in n-hexane afforded (E)-ethyl 4-(tert-butoxycarbonylamino)-2-fluorobut-2-enoate (0.525 g, 85%) as a clear oil and a mixture of 10:1 E:Z; E(major)-isomer 1H-NMR (200 MHz, CDCl3): δppm: 1.36 (3H, t, J 7.0 Hz), 1.45 (9H, s), 4.17 (2H, m), 4.32 (2H, q, J 7.0 Hz), 4.88 (1H, br s), 6.01 (1H, dt, J 19.5, 7.2).

1. extractionthe organic layer extracted with diethyl ether (50 mL)
2. washwashed with brine (20 mL)
3. dry with materialdried over MgSO4
4. filtrationfiltered
5. customthe solvent removed under reduced pressure
6. customto afford the crude product as a clear oil (0.850 g)
7. customPurification by flash chromatography (silica, ˜4 g)
8. washeluting in 5-15% EtOAc in n-hexane

ORD record

ord-4c043755a9e94fab990f80e5776f3825

Source dataset

uspto-grants-2013_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08426587B2