Ethyl Acetate → 2-[3-[2-(t-Butyldiphenylsilyloxy)ethylthio]-1-[(4-chlorophenyl)sulfonyl]propyl]-1,4-difluorobenzene

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Reaction Steps

The 2-[(4-chlorophenyl)sulfonylmethyl]-1,4-difluorobenzene (900 mg, 2.97 mmol) obtained in Example 5 and 2-[2-(t-butyldiphenylsilyloxy)ethylthio]ethanol (1.64 g, 4.55 mmol) were dissolved in toluene (20 ml), followed by the addition of cyanomethylenetri-n-butylphosphorane (1.26 g, 5.22 mmol). Under an argon atmosphere, the resulting mixture was heated under reflux for 9 hours. After the reaction mixture was allowed to cool down, 2-[2-(t-butyldiphenylsilyloxy)ethylthio]ethanol (500 mg, 1.39 mmol) and cyanomethylenetri-n-butylphosphorane (400 mg, 1.66 mmol) were added thereto. Under an argon atmosphere, the mixture was heated under reflux for 14 hours. After the reaction mixture was allowed to cool down, it was concentrated under reduced pressure. The residue was subjected to flash silica gel chromatography, and the fraction obtained from the hexane:ethyl acetate=10:1 eluate was concentrated under reduced pressure, whereby the title compound (1.82 g, 2.82 mmol, 95%) was obtained as a pale yellowish brown oil.

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