Potassium tert-butoxide → 2-(4-Ethoxy-2,3-difluorophenyl)-5-vinylselenophene

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Reaction Steps

3.0 g (8.4 mmol) of methyltriphenylphosphonium bromide are initially introduced in 50 ml of THF at 0° C., and 0.89 g (7.9 mmol) of potassium tertbutoxide is dissolved in 7 ml of THF is added. After 1.5 h at RT, 2.0 g (6.4 mmol) of 5-(4-ethoxy-2,3-difluorophenyl)selenophene-2-carbaldehyde are added, and the batch is stirred for 2.5 h. The mixture is diluted with MTBE, and water and 2 N hydrochloric acid are added. The organic phase is separated off, and the aqueous phase is extracted with MTBE. The combined organic phases are washed with sat. sodium chloride soln. and dried using sodium sulfate. The solution is concentrated to dryness, and the residue is purified by column chromatography (SiO2, n-heptane:EtOAc=10:1→5:1). Further purification is carried out by recrystallisation from n-heptane; 2-(4-ethoxy-2,3-difluorophenyl)-5-vinylselenophene is obtained as a yellow-orange solid.

Provenance & Evidence