Reaktion #575332

Reaktionsgleichung

farnesyl bromide

Methyl acetoacetate

sodium hydride

→

crude product

Methyl 3-oxo-7,11,15-trimethylhexadeca-6,10,14-trienoate

Lösungsmittel

THF

hexane

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThe yellow solution was stirred 15 min at 0° C.
2. 2
   workup.STIRRINGThe cloudy orange solution was stirred at 20° C. for 1 1/2 hours
3. 3
   Sonstigequenched by dropwise addition of saturated aqueous NH4Cl solution
4. 4
   workup.ADDITIONThe resulting mixture was diluted with ethyl acetate
5. 5
   Waschenwashed with water
6. 6
   Sonstigedried
7. 7
   Filtrationfiltered
8. 8
   Sonstigeevaporated

Vorschrift

Methyl acetoacetate (225 μL, 2.1 mmol) was added dropwise to a stirred suspension of sodium hydride (50% oil suspension, prewashed with hexane) (100 mg, 2.1 mmol) in anhydrous THF (5 mL) at 0° C. under an Argon atmosphere. The resulting solution was stirred 15 minutes at 0° C. and then treated with a 1.6 M solution (1.3 mL, 2.1 mmol) of n-butylithium in hexane over 2 minutes. The yellow solution was stirred 15 min at 0° C. and then treated dropwise with farnesyl bromide (545 KL, 2.0 mmol). The cloudy orange solution was stirred at 20° C. for 1 1/2 hours and then quenched by dropwise addition of saturated aqueous NH4Cl solution. The resulting mixture was diluted with ethyl acetate and washed with water, dried, filtered and evaporated to give the crude product which was used in the next step without purification. Diagnostic peaks in the NMR (300 MHz, CDCl3): δ 1.600 (6H, s), 1.614 (3H,s), 1.68 (3H, s), 1.9-2.1 (8H, m), 2.2-2.33 (2H, m), 2.58 (2H, t, J=6Hz), 3.448 (2H, s), 3.740 (3H,s), 5.05-5.15 (3H, m).

Quelle