Reaktion #305440

Reaktionsgleichung

31

2,3,4-Tri(t-butyldimethylsilyloxy)benzaldehyde

n-Butyl lithium

3,4,5-trimethoxybenzylphosphonium bromide

water

→

32

1,2,3-Tri(t-butyldimethylsilyloxy)-6-[(Z)-2-(3,4,5-trimethoxyphenyl)vinyl]-benzene

Lösungsmittel

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto warm to room temperature
2. 2
   workup.STIRRINGwith stirring overnight
3. 3
   TemperaturThe reaction mixture was cooled to 0° C.
4. 4
   ExtraktionThe reaction mixture was extracted with TBME (3×)
5. 5
   Waschenthe organic phase was washed successively with water and brine
6. 6
   Trocknendried (Na2SO4)
7. 7
   Einengenconcentrated in vacuo
8. 8
   Sonstigeto give crude product (1.5 g)
9. 9
   SonstigePurification by column chromatography (SiO2; 5:95 TBME:cyclohexane+1% Et3N)

Vorschrift

n-Butyl lithium (0.89 mL, 2.23 mmol, 2.5 M in hexanes) was added dropwise over 10 min to a solution of 3,4,5-trimethoxybenzylphosphonium bromide (0.96 g, 1.83 mmol) in THF (10 mL) at −10° C. The reaction mixture was stirred at this temperature for 15 min then cooled to −70° C. and a solution of 31 (0.93 g, 1.88 mmol) in THF (4 mL) was added and the reaction mixture was allowed to warm to room temperature with stirring overnight. The reaction mixture was cooled to 0° C. and water was added. The reaction mixture was extracted with TBME (3×) and the organic phase was washed successively with water and brine, dried (Na2SO4) and concentrated in vacuo to give crude product (1.5 g). Purification by column chromatography (SiO2; 5:95 TBME:cyclohexane+1% Et3N) gave 32 compound (0.6 g, 50%) as a 86:14 mixture of Z:E isomers:

Quelle