Réaction #415089

Équation de réaction

methyl chloroformate

acetylene

n-butyllithium

hexane EtOAc

→

title compound

Rendement 87.0%

(E)-7,11-Dimethyl-6,10-dodecadien-2-ynoic acid, methyl ester

Rendement 87.0%

Solvants

THF

—

hexanes

Conditions de réaction

Traitement

1. 1
   Autreat -78° C.
2. 2
   Autreto give a purple solution
3. 3
   workup.ADDITIONwas added
4. 4
   Autreto give a yellow solution
5. 5
   Autrewas quenched with saturated NH4Cl
6. 6
   workup.ADDITIONdiluted with diethyl ether
7. 7
   ExtractionThe ether extract
8. 8
   Lavagewas washed with water, saturated NaHCO3, brine
9. 9
   Séchagedried over MgSO4
10. 10
    Autreevaporated
11. 11
    Autreto provide 1.73 g of a crude yellow oil
12. 12
    Lavageeluted with 20:1 hexane/EtOAc collecting 20 mL fractions
13. 13
    Autreevaporated

Mode opératoire

A solution of 1.15 g (6.54 mmol) of Example 16, Part A acetylene in 15 mL of THF at -78° C. under argon was treated with 4.5 mL (7.19 mmol) of 1.6 M n-butyllithium in hexanes over 10 minutes to give a purple solution. The reaction was allowed to stir at -78° C. for 1 hour when 1 mL (13.1 mmol) of methyl chloroformate was added to give a yellow solution. The reaction was allowed to stir at -78° C. for 1 hour when it was quenched with saturated NH4Cl and diluted with diethyl ether. The ether extract was washed with water, saturated NaHCO3, brine, dried over MgSO4 and evaporated to provide 1.73 g of a crude yellow oil. Flash chromatography was performed on 180 g of silica gel packed and loaded with 25:1 hexane/EtOAc and eluted with 20:1 hexane/EtOAc collecting 20 mL fractions. Fractions 59 to 83 were combined and evaporated to provide 1.34 g (87%) of title compound in the form of a pale yellow oil.

Source