Reaktion #47420

Reaktionsgleichung

2-fluoro-3-methyl-phenol

ethyl-2-butynoate

1,8-diazabicyclo[5.4.0]undec-7-ene

→

(E)-3-(2-fluoro-3-methyl-phenoxy)-but-2-enoic acid ethyl ester

Ausbeute 23.0%

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONAfter addition
2. 2
   Temperaturat reflux overnight
3. 3
   Sonstigewas removed in vacuo
4. 4
   workup.ADDITIONthe residue was diluted in diethyl ether
5. 5
   Waschenwashed first with 1N aqueous hydrochloric acid
6. 6
   Trocknen10% aqueous sodium hydroxide solution, a saturated sodium chloride solution and dried over magnesium sulfate
7. 7
   FiltrationThe mixture was filtered
8. 8
   Sonstigeevaporated
9. 9
   Sonstigeresidue purified by ISCO flash chromatography (Teledyne Isco RediSep Flash Column 330 g, 0% to 15% ethyl acetate/hexanes) which

Vorschrift

To a stirred mixture of 2-fluoro-3-methyl-phenol (20.0 g, 0.158 mol) and ethyl-2-butynoate (33.6 g, 0.300 mol) in tetrahydrofuran (100 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (25.4 g, 0.167 mol) slowly. After addition was complete the mixture was stirred at reflux overnight. Upon completion of the reaction the tetrahydrofuran was removed in vacuo and the residue was diluted in diethyl ether and washed first with 1N aqueous hydrochloric acid, then 10% aqueous sodium hydroxide solution, a saturated sodium chloride solution and dried over magnesium sulfate. The mixture was filtered and evaporated and residue purified by ISCO flash chromatography (Teledyne Isco RediSep Flash Column 330 g, 0% to 15% ethyl acetate/hexanes) which afforded (E)-3-(2-fluoro-3-methyl-phenoxy)-but-2-enoic acid ethyl ester (8.40 g, 23%) as a clear oil.

Quelle