تفاعل #547230

معادلة التفاعل

Ethyl bromoacetate

triphenylphosphine

triisopropyl-(2-methyl-furan-3-ylmethoxy)-silane

Triisopropyl-(2-methyl-furan-3-ylmethoxy)-silane

n-butyl lithium

furyl-zinc chloride

→

compound 29

(5-Methyl-4-triisopropylsilanyloxymethyl-furan-2-yl)-acetic acid ethyl ester

المذيبات

tetrahydrofuran

tetrahydrofuran

tetrahydrofuran

ظروف التفاعل

المعالجة

1. 1
   workup.WAITto stand for a further 1 hour at room temperature
2. 2
   درجة الحرارةcooled (−5° C.)
3. 3
   أخرىThe resulting reaction mixture
4. 4
   درجة الحرارةto warm to room temperature
5. 5
   workup.STIRRINGthen stirred for a further 16 hours at room temperature
6. 6
   أخرىThe reaction was quenched by the addition of saturated ammonium chloride solution (100 mL)
7. 7
   استخلاصextracted with ethyl acetate (3×150 mL)
8. 8
   غسيلThe combined organic extracts were successively washed with water (200 mL) and brine (250 mL)
9. 9
   أخرىdried
10. 10
    ترشيحfiltered
11. 11
    تركيزconcentrated in vacuo
12. 12
    أخرىThe residue was purified by flash chromatography
13. 13
    غسيلa gradient elution (diethyl ether/petroleum ether (40–60°) 1:49 to 1:25 by volume)

الإجراء التجريبي

A solution of triisopropyl-(2-methyl-furan-3-ylmethoxy)-silane (14) (5.0 g) in tetrahydrofuran (15 mL) was cooled to −78° C. with stirring. This solution was treated drop-wise with n-butyl lithium (2.5 M in hexanes, 8.94 mL). The resulting solution was warmed to 0° C. and allowed to stand for 30 minutes after which a solution of dried zinc chloride (3.04 g) in tetrahydrofuran (10 mL) was added and the resulting solution allowed to stand for a further 1 hour at room temperature. Concurrently, a second reaction vessel was charged with tetrahydrofuran (10 mL), nickel(II) acetylacetonate (120 mg), and triphenylphosphine (122 mg) and cooled (−5° C.). Ethyl bromoacetate (1.03 mL) was added to this mixture, followed by the addition of the previously prepared solution of the furyl-zinc chloride. The resulting reaction mixture was allowed to warm to room temperature then stirred for a further 16 hours at room temperature. The reaction was quenched by the addition of saturated ammonium chloride solution (100 mL) and extracted with ethyl acetate (3×150 mL). The combined organic extracts were successively washed with water (200 mL) and brine (250 mL), dried, filtered and concentrated in vacuo. The residue was purified by flash chromatography using a gradient elution (diethyl ether/petroleum ether (40–60°) 1:49 to 1:25 by volume) to give compound 29 as a clear oil (1.44 g). LC/MS System A: Rt=5.16 min.

المصدر