Azobisisobutyronitrile → 1-(Bromomethyl)-3-(1,1,2,2-tetrafluoroethoxy)benzene

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Reaction Steps

To a solution of 3-(1,1,2,2-tetrafluoroethoxy)toluene (2.84 ml, 16.8 mmol) in ethyl acetate (30 ml) were added N-bromosuccinimide (3.0 g, 16.8 mmol) and 2,2′-azobisisobutyronitrile (0.1 g) and the mixture was heated under reflux for 2 hrs. The reaction solution was concentrated under reduced pressure and diethyl ether and hexane were added. Insoluble material was removed and washed with diethyl ether. The filtrate was evaporated under reduced pressure to give 3-(1,1,2,2-tetrafluoroethoxy)-1-bromomethylbenzene. To a solution of ethyl 3-[4-(methylsulfonyl)phenyl]-3-oxopropanoate (3.5 g, 13.0 mmol) in 1,2-dimethoxyethane (30 ml) was added sodium hydride (0.52 g, 60% in oil, 13.0 mmol) under ice-cooling and the mixture was stirred for 10 min. A solution of 3-(1,1,2,2-tetrafluoroethoxy)-1-bromomethylbenzene obtained above in 1,2-dimethoxyethane (5 ml) was dropwise added, and the mixture was stirred at room temperature for 4 hrs. To the reaction solution was added water (100 ml) and the mixture was extracted with ethyl acetate (100 ml). The extract was washed with water, dried over anhydrous magnesium sulfate and evaporated under reduced pressure. The residue was purified by silica gel chromatography (hexane:ethyl acetate=3:1-2:1) to give the objective substance (3.03 g, 49%) as an oil.

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