Reaction #3860

Reaction equation

carbonate

potassium carbonate

1,4-dioxane

(Z,Z)-11,13-hexadecadienal

→

(Z,Z)-1,12,14-heptadecatriene

Solvents

water

Conditions

Workup

1. 1
   Otherwas prepared in a 100 ml round bottomed flask
2. 2
   Otherequipped with a magnetic stirrer
3. 3
   Temperaturethermometer and reflux condenser
4. 4
   TemperatureThe mixture was heated
5. 5
   Temperatureto reflux at 105°-110°
6. 6
   Otherwere withdrawn periodically
7. 7
   Otherpartitioned between 1 ml of H2O and 1 ml of hexane
8. 8
   Otherat 1.1 and 2.2 and 17 hr
9. 9
   workup.ADDITIONMore potassium carbonate (1.7 g) was added at 212 hr
10. 10
    Otherthe reaction to completion
11. 11
    TemperatureThe reaction mixture was cooled
12. 12
    Extractionextracted 3 times with 25 ml of hexane
13. 13
    Extractionthe organic layer was extracted with water
14. 14
    Otherdried
15. 15
    Otherthe solvent removed

Procedure

(Z,Z)-1,12,14-heptadecatriene (TRIENE) was synthesized conveniently from Wittig Salt and aldehyde in aqueous dioxidepotassium carbonate heterogeneous medium (Lechat 1982). A mixture of 3.57 g (0.01 mol) of methyl triphenylphosphonium bromide (Alfa Inorganics), 1.7 g (0.14 mol) of potassium carbonate, 10 ml of 1,4-dioxane, 0.15 ml of water and 2.36 g (0.01 mol) of (Z,Z)-11,13-hexadecadienal (AL. Albany International) was prepared in a 100 ml round bottomed flask equipped with a magnetic stirrer, thermometer and reflux condenser. The mixture was heated to reflux at 105°-110° with stirring while aliquots of 15 ul were withdrawn periodically and partitioned between 1 ml of H2O and 1 ml of hexane. Analysis by gas-liquid chromatography, showed 66, 70 and 99% triolefin and 30%, 26% and 1% starting aldehyde at 1.1 and 2.2 and 17 hr, respectively. More potassium carbonate (1.7 g) was added at 212 hr to drive the reaction to completion. The reaction mixture was cooled and extracted 3 times with 25 ml of hexane, then the organic layer was extracted with water, dried and the solvent removed to leave 1.8 g of yellow oil and a few crystals of triphenylphosphine oxide. The oil was taken up in hexane and passed through a 1×45 cm column of silica gel (60-200 mesh, Baker) with hexane, to yield 1.7 g (73% yield) of clear oil.

Source