Ammonium Chloride → (S)-(-)-4,4,4-Trifluoro-3-hydroxy-3-methyl-1-(4-phenylsulfonylphenyl)-trans-but-1-ene

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Reaction Steps

(2S)-1,1,1-Trifluoro-2-methyl-4-(4-phenylsulfonylphenyl)-2,3-butanediol. To a stirred, cooled 0° C. solution of 3-hydroxy-3-methyl-1-(4-phenylsulfonylphenyl)-4,4,4-trifluoro-2-butanone (3.7 g, 10 mmol) in 135 mL methanol was added NaBH4 (1.7 g, 44 mmol). The mixture was stirred for 15 minutes. 100 mL of saturated aqueous NH4Cl was added. The mixture was extracted with dichloromethane and the combined organic layers were dried and evaporated. The resulting solid was pre-absorbed onto silica gel and purified by chromatography, with ether:hexane as the eluent (75:25), to give the title compound as a mixture of isomers (3.13 g, 83%); NMR (CDCl3): 7.96-7.89 (m,4, Ar), 7.58-7.49 (m,3, Ar), 7.48-7.39 (d,2, Ar), 3.91-3.86 (m,2), 3.13 (s,1), 3.08 (s,1), 2.80 (s,1), 2.76-2.75 (d,1), 2.68 (s,1), 1.47 (s,3, CH3); MS: m/z=375(M+1).

Provenance & Evidence