反应详情

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.

1. additionAfter addition
2. temperatureat reflux overnight
3. customwas removed in vacuo
4. additionthe residue was diluted in diethyl ether
5. washwashed first with 1N aqueous hydrochloric acid
6. dry with material10% aqueous sodium hydroxide solution, a saturated sodium chloride solution and dried over magnesium sulfate
7. filtrationThe mixture was filtered
8. customevaporated
9. customresidue purified by ISCO flash chromatography (Teledyne Isco RediSep Flash Column 330 g, 0% to 15% ethyl acetate/hexanes) which