Triethyl phosphite → Triethyl 2-fluoro-2-phosphonoacetate
Reaction equation
Br[CH:2]([F:8])[C:3]([O:5][CH2:6][CH3:7])=[O:4].[P:9]([O:16]CC)([O:13][CH2:14][CH3:15])[O:10][CH2:11][CH3:12]>>[CH3:7][CH2:6][O:5][C:3]([CH:2]([P:9]([O:13][CH2:14][CH3:15])([O:10][CH2:11][CH3:12])=[O:16])[F:8])=[O:4]Participants
Procedure
Ethyl bromofluoroacetate (ex Fluorochem) (25 g) and triethyl phosphite (ex Aldrich) (29 g) were heated together at 140°-5° for 6 hours in a vessel equipped with a fractionating column. When all the ethyl bromide had distilled off the residue was distilled to give triethyl 2-fluoro-2-phosphonoacetate (22 g) (bp 98°-108° at 0.8 mm). The latter (20 g) was added dropwise to hexane washed sodium hydride (3.3 g of 60% dispersion) in dry ether (85 ml). After 3 hours at room temperature and 30 mins under reflux, acetone (6.1 ml) was added and the mixture stirred for 4 days at room temperature under nitrogen. After conventional work up the crude product was distilled to give ethyl 2-fluoro-3-methyl-but-2-enoate (4 g) (bp. 60°-2° at 15 mm). (Ref. Machledit & Wessendorf. Ann. 674, 1, (1964)).
Workup
- customequipped with a fractionating column
- distillationWhen all the ethyl bromide had distilled off the residue
- distillationwas distilled
Sources & evidence
- ORD record
- ord-92313ae580ae4f559fd0a5371bc03ad8
- Source dataset
- uspto-grants-1993_01
- Patent number
- US05180737
Reaction notes
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