반응 #50480

반응 방정식

hexamethylphosphoramide

farnesyl bromide

(E,E) -3,7,11-Trimethyl-2,6,10-dodecatrienyl bromide

diisopropylamine

n-butyllithium

t-butyl acetate

→

title compound

수율 65.0%

(E,E)-5,9,13-Trimethyl-4,8,12-tetradecatrienoic acid, 1,1-dimethylethyl ester

수율 65.0%

용매

THF

—

hexanes

tetrahydrofuran

반응 조건

후처리

1. 1
   기타was recooled to -78° C.
2. 2
   기타quenched with saturated NH4Cl
3. 3
   온도to warm to room temperature
4. 4
   workup.ADDITIONAfter diluting with 400 mL of ethyl acetate
5. 5
   세척the mixture was washed with four 100 mL portions of water, and 200 mL of brine
6. 6
   건조dried over MgSO4
7. 7
   기타evaporated
8. 8
   기타to provide 12.96 g of crude product as a yellow oil
9. 9
   기타Purification by flash chromatography on 1 kg of silica gel
10. 10
    세척eluted with 1:9 ethyl acetate

실험 절차

To a solution of 9.60 mL (68.5 mmol, 1.5 eq.) of diisopropylamine in 100 mL of tetrahydrofuran (THF) at -78° C. under argon was added 28.2 mL (45.0 mmol, 1.0 eq.) of 1.6M n-butyllithium in hexanes over 20 minutes. After warming to 0° C. for 15 minutes, the solution was recooled to -78° C. and 6.05 mL (45 mmol, 1.0 eq.) of t-butyl acetate was added over 20 minutes. After an additional 15 minutes, 16.0 mL (92 mmol, 2.05 eq.) of hexamethylphosphoramide (HMPA) was added, followed by a solution of 12.53 g (45.0 mmol) of Part A(1) farnesyl bromide in 100 mL of THF over 20 minutes. The reaction was stirred at -78° C. for 2.5 hours, quenched with saturated NH4Cl and allowed to warm to room temperature. After diluting with 400 mL of ethyl acetate, the mixture was washed with four 100 mL portions of water, and 200 mL of brine, dried over MgSO4 and evaporated to provide 12.96 g of crude product as a yellow oil. Purification by flash chromatography on 1 kg of silica gel, eluted with 1:9 ethyl acetate:petroleum ether afforded 9.39 g (65%) of title compound as a pale yellow oil.

출처