Ethyl 2-butynoate → (E)-3-(2,6-difluoro-3-methoxy-phenoxy)-but-2-enoic acid ethyl ester

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Reaction Steps

To a stirred mixture of 2,6-difluoro-3-methoxy-phenol (5.00 g, 0.031 mol) and ethyl-2-butynoate (7.00 g, 0.062 mol) in tetrahydrofuran (40 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (4.76 g, 0.031 mol) in tetrahydrofuran (10 mL) 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 the residue purified by ISCO column chromatography (Teledyne Isco RediSep Flash Column 120 g, 0% to 15%) ethyl acetate/hexanes which afforded (E)-3-(2,6-difluoro-3-methoxy-phenoxy)-but-2-enoic acid ethyl ester (6.42 g, 76%) as a colorless oil.

Provenance & Evidence