Phosphorus tribromide → 1-Bromo-2-(3-bromo-1-propen-1-yl)benzene

All of the o-bromocinnamylalcohol (159 mM) from Step A was dissolved in 300 ml of carbon tetrachloride under nitrogen and chilled to 0°. Then 100 ml of carbon tetrachloride containing phosphorous tribromide (5.62 ml; 59.8 mM) was added dropwise. After stirring at 0° for an additional hour the reaction was poured into ice water and partitioned. The aqueous layer was extracted once with methylene chloride and the combined organic layers were washed with cold 1.5N aqueous sodium hydroxide. Drying over magnesium sulfate followed by solvent removal gave a pale yellow oil, which was purified by short path distillation at 0.2 torr. The o-bromocinnamyl bromide was distilled at 105° and 37.3 g (85% yield) was isolated.

1. temperaturechilled to 0°
2. additionwas added dropwise
3. custompartitioned
4. extractionThe aqueous layer was extracted once with methylene chloride
5. washthe combined organic layers were washed with cold 1.5N aqueous sodium hydroxide
6. dry with materialDrying over magnesium sulfate
7. customfollowed by solvent removal
8. customgave a pale yellow oil, which
9. distillationwas purified by short path distillation at 0.2 torr
10. distillationThe o-bromocinnamyl bromide was distilled at 105°
11. custom37.3 g (85% yield) was isolated

ORD record

ord-4d20c03e2dff4b738e0fc10793862dea

Source dataset

uspto-grants-1987_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04686235