反应详情

34.45 g (258.91 mmol) of aluminum trichloride is introduced into 354.35 g (237.02 mmol) of 4-bromoanisole. 38.95 g (172.19 mmol) of 2-hydroxy-4-methylene-2-(trifluoromethyl)pentanoic acid ethyl ester is added in drops to this mixture within one hour. After stirring overnight at room temperature, the batch is added to ice water and made acidic with 10% hydrochloric acid. After 3× extraction with ethyl acetate, the combined organic extracts are washed with 1N hydrochloric acid and brine. After drying on magnesium sulfate, the solvent is spun off. Most of the excess 4-bromoanisole is distilled off (10 mbar; bath temperature 110° C.). After chromatography on silica gel (mobile solvent ethyl acetate/hexane), 36.87 g (51.8%) of the desired compound is obtained.

1. extractionAfter 3× extraction with ethyl acetate
2. washthe combined organic extracts are washed with 1N hydrochloric acid and brine
3. customAfter drying on magnesium sulfate
4. distillationMost of the excess 4-bromoanisole is distilled off (10 mbar; bath temperature 110° C.)