반응 #522746

반응 방정식

2-ethyl-3,6,6-trimethyl-2-cyclohexene-1-carboxylic acid ethyl ester

lithium

allyl phenyl ether

→

2-ethyl-3,6,6-trimethyl-1-[but-3-enoyl]-2-cyclohexene

수율 85.1%

용매

ether

tetrahydrofuran

ether

반응 조건

후처리

1. 1
   workup.ADDITIONA few crystals of diphenyl are added to a suspension
2. 2
   온도cooled to 5°-10° C
3. 3
   workup.ADDITIONAfter a greenish coloration sets in, the rest of the solution is added dropwise at -15° C
4. 4
   workup.ADDITIONAfter completion of the addition
5. 5
   기타The resulting allyl lithium solution is decanted off from excess lithium
6. 6
   기타transferred to a dropping funnel
7. 7
   workup.ADDITIONThis solution is added dropwise to a solution
8. 8
   온도cooled to -60° C
9. 9
   workup.ADDITIONAfter completion of the addition
10. 10
    workup.WAITthe mixture is left
11. 11
    온도to warm to room temperature
12. 12
    추출extracted with three portions of hexane
13. 13
    세척The combined hexane extracts are washed neutral with three portions of water
14. 14
    건조dried over sodium sulphate
15. 15
    기타evaporated
16. 16
    workup.DISTILLATIONBy fractional distillation of the residue there

실험 절차

A few crystals of diphenyl are added to a suspension, cooled to 5°-10° C and held under a nitrogen atmosphere, of 2.4 g (0.35 g-atoms) of finely cut lithium wire in 40 ml of absolute tetrahydrofuran. 2 ml of a solution of 9.4 g (70 mmol) of allyl phenyl ether in 10 ml of absolute ether are then added. After a greenish coloration sets in, the rest of the solution is added dropwise at -15° C. After completion of the addition, the mixture is stirred for 30 minutes at 0° C. The resulting allyl lithium solution is decanted off from excess lithium and transferred to a dropping funnel. This solution is added dropwise to a solution, cooled to -60° C and maintained under nitrogen, of 4.48 g (20 mmol) of 2-ethyl-3,6,6-trimethyl-2-cyclohexene-1-carboxylic acid ethyl ester in 40 ml of absolute ether. After completion of the addition, the mixture is left to warm to room temperature, poured on to ice-water and extracted with three portions of hexane. The combined hexane extracts are washed neutral with three portions of water, dried over sodium sulphate and evaporated. By fractional distillation of the residue there are obtained 3.75 g (85%) of 2-ethyl-3,6,6-trimethyl-1-[but-3-enoyl]-2-cyclohexene; boiling point 57°-58° C/0.04 mm Hg; nD20 = 1.4865.

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