3-(3-Bromophenyl)propanal → 1-Bromo-3-(but-3-en-1-yl)benzene

Temperature

0 °C

A solution of 1.34 gm (3.77 mmol) of methyltriphenylphosphonium bromide in THF at 0° C. was treated dropwise with 2.3 mL of 1.6 M n-BuLi in hexanes (3.77 mmol), stirred at 0° C. for 0.25 h, cooled to −78° C., treated dropwise with a solution of 3-(3-bromophenyl)propionaldehyde (0.7 gm, 3.28 mmol) in THF, stirred at −78° C. for 1 h, allowed to warm to room temperature, quenched with aqueous NH4Cl and concentrated under reduced pressure. The resultant residue was taken up in EtOAc, washed sequentially with water and brine, dried over Na2SO4 and concentrated under reduced pressure. Chromatography of this concentrate on silica gel with a gradient of 0.5% EtOAc-hexanes to 2.0% EtOAc-hexanes gave 1-bromo-3-but-3-enylbenzene as an oil, 0.35 gm (50% yield); 1H NMR (400 MHz, CDCl3) δ: 2.33 (m, 2H), 2.66 (t, 2H, J=7.4 Hz), 4.98 (m, 2H), 5.79 (m, 1H), 7.12 (m, 2H), 7.30 (m, 2H).

1. temperaturecooled to −78° C.
2. stirringstirred at −78° C. for 1 h
3. temperatureto warm to room temperature
4. customquenched with aqueous NH4Cl
5. concentrationconcentrated under reduced pressure
6. washwashed sequentially with water and brine
7. dry with materialdried over Na2SO4
8. concentrationconcentrated under reduced pressure
9. concentrationChromatography of this concentrate on silica gel with a gradient of 0.5% EtOAc-hexanes to 2.0% EtOAc-hexanes

ORD record

ord-deada4722d54478c8ba908846902f910

Source dataset

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07423158B2