تفاعل #2348120

معادلة التفاعل

water

3,5-dimethoxybenzaldehyde

4-methoxy-benzyltriphenylphosphonium bromide

n-butyllithium

→

solid

المردود 86.0%

5[(E)-2-(4-Hydroxyphenyl)-vinyl]benzene 1,3-diol

المردود 86.0%

المذيبات

tetrahydrofuran

tetrahydrofuran

ظروف التفاعل

المعالجة

1. 1
   workup.STIRRINGthe mixture stirred for 6-15 h
2. 2
   استخلاصextracted with dichloromethane
3. 3
   غسيلThe organic phase was washed with water, and removal of the solvent in vacuo
4. 4
   أخرىafforded an oil
5. 5
   أخرىThe oil was separated by flash column chromatography (49:1 hexane/ethyl acetate)
6. 6
   غسيلThe cis-stilbene eluted first as a clear oil
7. 7
   workup.ADDITIONTo a solution of the trans isomer (3.1. g) in anhydrous dichloromethane (150 mL) at −78° C. was added (dropwise) boron tribromide (1.0 M, 34.5 mL)
8. 8
   workup.STIRRINGthe resulting red solution was stirred under argon for 30 min
9. 9
   workup.ADDITIONThe solution was poured into water
10. 10
    استخلاصextracted with dichloromethane
11. 11
    غسيلThe organic phase was washed with water, and removal of the solvent in vacuo
12. 12
    أخرىafforded an oil, which
13. 13
    أخرىwas separated by flash column chromatography (1:1 hexane/ethyl acetate)

الإجراء التجريبي

To a solution of 4-methoxy-benzyltriphenylphosphonium bromide (12.5 g) in anhydrous tetrahydrofuran (200 mL) at −78° C. was added n-butyllithium (2.44 M, 1.0 equiv), and the resulting red solution was stirred under argon for 2-4 h. A solution of 3,5-dimethoxybenzaldehyde (4.5 g) in tetrahydrofuran was added dropwise over 30 min and the mixture stirred for 6-15 h. The resulting cream suspension was poured into water and extracted with dichloromethane. The organic phase was washed with water, and removal of the solvent in vacuo afforded an oil. The oil was separated by flash column chromatography (49:1 hexane/ethyl acetate). The cis-stilbene eluted first as a clear oil followed by the trans isomer as a colorless solid or oil. Overall yield: 91%. To a solution of the trans isomer (3.1. g) in anhydrous dichloromethane (150 mL) at −78° C. was added (dropwise) boron tribromide (1.0 M, 34.5 mL), and the resulting red solution was stirred under argon for 30 min. The solution was poured into water and extracted with dichloromethane. The organic phase was washed with water, and removal of the solvent in vacuo afforded an oil, which was separated by flash column chromatography (1:1 hexane/ethyl acetate) to afford a colorless solid (2.26 g, 86%): mp 260° C.

المصدر