Reaction #65056

Reaction equation

benzaldehyde

sodium hydroxide

3-acetyl-5-butyldihydro-2(3H)-furanone

water

→

(E)-3-(phenylmethylene)-5-butyldihydro-2 (3H)-furanone

Yield 64.5%

Solvents

toluene

Conditions

Workup

1. 1
   workup.ADDITIONcharged to a 500 mL flask
2. 2
   Otherfitted with a mechanical stirrer
3. 3
   Otherwas removed in the Dean-Stark trap
4. 4
   TemperatureThe reaction was further heated
5. 5
   Temperatureunder reflux for an additional 2.5 hours
6. 6
   TemperatureThe reaction mixture was then cooled to room temperature
7. 7
   Washwashed with 3×80 ml of water
8. 8
   ExtractionThe water layer was extracted with 50 ml of toluene
9. 9
   WashThe toluene solution was then washed with 100 ml of saturated sodium chloride
10. 10
    Dryingdried over Na2SO4
11. 11
    Concentrationconcentrated to 35.4 gms of an orange oil under rotoevaporation
12. 12
    workup.DISTILLATION19.0 gms of this oil was subjected to simple straight takeover distillation (0.04 mm Hg: 25°-147° C.)

Procedure

To a mixture of 36.8 g (0.200 mole) of 3-acetyl-5-butyldihydro-2(3H)-furanone in 200 mL of toluene charged to a 500 mL flask fitted with a mechanical stirrer, Dean-Stark trap and an addition funnel was added 8.00 g (0.200 mole) of sodium hydroxide at once. The mixture was vigorously stirred for 10 mins. at room temperature and then heated under reflux for 1 hour while water was removed in the Dean-Stark trap. After the one hour period 23.9 g (0.225 mole) of benzaldehyde was added to the refluxing solution in 4-5 ml aliquats in 1 hour. The reaction was further heated under reflux for an additional 2.5 hours. The reaction mixture was then cooled to room temperature and washed with 3×80 ml of water. The water layer was extracted with 50 ml of toluene and the toluene layers combined. The toluene solution was then washed with 100 ml of saturated sodium chloride and dried over Na2SO4 and concentrated to 35.4 gms of an orange oil under rotoevaporation. 19.0 gms of this oil was subjected to simple straight takeover distillation (0.04 mm Hg: 25°-147° C.) to leave 16 g (64.5% yield) of (E)-3-(phenylmethylene)-5-butyldihydro-2 (3H)-furanone as a viscous liquid. 1HNMR (CDCl3) δ7.5 (m, 6H), 4.56 (pentet, 1H), 3.3 (ddd, 1H), 2.8 (ddd, 1H), 1.9-1.2 (m, 6H), 0.86 (t, 3H).

Source