2-Bromo-5-fluorobenzaldehyde → 1-Bromo-2-ethenyl-4-fluorobenzene

Temperature

0 °C

21.12 g Methyltriphenylphosphonium bromide were suspended in 150 ml tetrahydrofuran and cooled in an ice bath. 21.68 ml n-butyl lithium (2.5 M in n-heptane) were added dropwise and the reaction mixture stirred at 0° C. for thirty minutes. Then 10.0 g commercially available 2-bromo-5-fluorobenzaldehyde were added slowly so that the reaction temperature did not exceed +5° C. After completion of the addition the cooling bath was removed and the reaction mixture stirred at room temperature for one hour. The reaction mixture was diluted by addition of 300 ml ethyl acetate and washed three times with portions of 120 ml brine. The organic phase was dried over MgSO4, the solvent removed in vacuo and the resulting residue purified on silica gel with the eluent heptane=>n-heptane:ethyl acetate=9:1 to obtain 7.9 g 1-Bromo-4-fluoro-2-vinyl-benzene as an oil.

1. temperaturecooled in an ice bath
2. customdid not exceed +5° C
3. additionAfter completion of the addition the cooling bath
4. customwas removed
5. stirringthe reaction mixture stirred at room temperature for one hour
6. additionThe reaction mixture was diluted by addition of 300 ml ethyl acetate
7. washwashed three times with portions of 120 ml brine
8. dry with materialThe organic phase was dried over MgSO4
9. customthe solvent removed in vacuo
10. customthe resulting residue purified on silica gel with the eluent heptane=>n-heptane

ORD record

ord-79f3e99cc7f940bfbc0671a11a63c2d5

Source dataset

uspto-grants-2010_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07834030B2