Reaction #1552073

Reaction equation

Methacrolein

5-methyl-3-methylenehex-1-ene

→

3a

Yield 48.0%

4-Isobutyl-1-methylcyclohex-3-enecarbaldehyde

Yield 48.0%

Solvents

toluene

Conditions

Workup

1. 1
   Temperaturea slight increase in temperature
2. 2
   workup.STIRRINGAfter stirring for 15 min
3. 3
   Otherto rise further to 31° C
4. 4
   workup.STIRRINGThe reaction mixture was stirred for 2 h
5. 5
   Otherquenched with sat. NaHCO3 solution (200 ml)
6. 6
   OtherAfter brief agitation the phases were separated
7. 7
   Extractionthe lower aqueous phase extracted with toluene (300 ml)
8. 8
   WashThe combined organic phases were washed with sat. sodium potassium tartrate solution (2×200 ml) and water (300 ml)
9. 9
   Dryingdried (Na2SO4)
10. 10
    Concentrationconcentrated in vacuo
11. 11
    workup.DISTILLATIONThe oil was purified by short Vigreux distillation at reduced pressure

Procedure

Anhydrous AlCl3 (0.6 g, 4.1 mmol) was suspended in toluene (250 ml) with vigorous stirring and a slow flow of nitrogen applied. Methacrolein (90% tech., 14 ml, 160 mmol) was added at room temperature over 10 min causing a slight increase in temperature. After stirring for 15 min, 5-methyl-3-methylenehex-1-ene 2 (25 g, 140 mmol) was added over 30 min causing the temperature to rise further to 31° C. The reaction mixture was stirred for 2 h and then quenched with sat. NaHCO3 solution (200 ml). After brief agitation the phases were separated and the lower aqueous phase extracted with toluene (300 ml). The combined organic phases were washed with sat. sodium potassium tartrate solution (2×200 ml) and water (300 ml), dried (Na2SO4) and concentrated in vacuo. The oil was purified by short Vigreux distillation at reduced pressure to give 3a as a colorless oil (12 g, 48% yield) containing ca. 10% GC of an isomer 3′a.

Source