Ammonium Chloride → Methyl 4-{(4E)-5-(5-fluoro-2-hydroxyphenyl)-3-[4-(methoxycarbonyl)benzyl]pent-4-en-1-yl}benzoate

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Reaction Steps

21.65 ml (54.12 mmol) of a 2.5 M solution of n-butyllithium in hexane are slowly added dropwise to a solution of 10.84 g (23.2 mmol) of (5-fluoro-2-hydroxybenzyl)(triphenyl)phosphonium bromide in 150 ml of THF at 0° C., and the mixture is stirred at this temperature for 45 min. Subsequently, at this temperature, 6.85 g (19.33 mmol) of dimethyl 4,4′-(2-formylbutane-1,4-diyl)dibenzoate in 100 ml of THF are slowly metered in. The reaction solution is stirred at 0° C. for 3 h and, after addition of saturated ammonium chloride solution, diluted with water and ethyl acetate, the organic phase is separated off and the aqueous phase is back-extracted twice more with ethyl acetate. The combined organic phases are dried over sodium sulphate and filtered, and the solvent is removed to dryness. The resulting crude product is purified by flash chromatography on silica gel (mobile phase: cyclohexane/ethyl acetate 4:1). 8.21 g (17.75 mmol, 76% of theory) of a yellowish oil are obtained.

Provenance & Evidence