Reaction #95467

Reaction equation

phosphorous tribromide

(Z,Z)-5,8-tetradecadien-2-yn-1-ol

→

(Z,Z)-1-bromo-5,8-tetradecadien-2-yne

Solvents

ether

ether

Conditions

Workup

1. 1
   TemperatureThe reaction mixture was heated
2. 2
   Temperatureunder reflux for 2.5 h
3. 3
   workup.ADDITIONpoured onto ice-water
4. 4
   ExtractionIt was extracted three times with ether
5. 5
   WashThe combined ether extracts were washed with dilute aqueous sodium bicarbonate solution, water
6. 6
   Dryingdried over Na2SO4
7. 7
   Concentrationconcentrated in vacuo
8. 8
   workup.DISTILLATIONEvaporative distillation of the crude product at 145°-148° C./0.15 mm

Procedure

A solution of phosphorous tribromide (0.47 g, 1.73 mmol) in absolute ether (0.5 ml) was added dropwise during five minutes to a mixture of (Z,Z)-5,8-tetradecadien-2-yn-1-ol (1.03 g, 5 mmol), and dry pyridine (14 mg, 0.18 mmol) in 8 ml of absolute ether. The reaction mixture was heated under reflux for 2.5 h, cooled to 23° C., then poured onto ice-water. It was extracted three times with ether. The combined ether extracts were washed with dilute aqueous sodium bicarbonate solution, water, dried over Na2SO4 and concentrated in vacuo. Evaporative distillation of the crude product at 145°-148° C./0.15 mm afforded 1.1 g (80.5%) of (Z,Z)-1-bromo-5,8-tetradecadien-2-yne as a pale yellow oil.

Source