α,α'-Dibromodibenzyl sulfone (CAS no.: ), which is also known as , 1,1-[sulfonylbis(bromomethylene)]bis-, could be produced through the following synthetic routes.

A. α-Bromophenylacetic acid. A 3-l., round-bottomed flask fitted with a mechanical stirrer and an efficient reflux condenser is charged with 750 ml. of benzene, 230 g. (1.69 moles) of phenylacetic acid, 15 g. (0.12 mole) of phosphorus trichloride and 288 g. (1.80 moles) of bromine. The resulting solution is heated at gentle reflux for 2–3 days until the initial bromine color is discharged. The solution is allowed to cool to room temperature and after 1 hour is decanted from some polymeric material into a 2-l. distilling flask. Removal of the solvent by distillation at water bath temperatures with the aid of a water aspirator gives a black oil which is poured into 250–300 ml. of ligroin (b.p. 90–120°). The mixture is heated, dissolving the oil, and the solution is stored at -25° in a freezer for 12 hours. Filtration on a sintered-glass funnel followed by washing with 200 ml. of cold (10°) ligroin (b.p. 90–120°) gives 243 g. (67%) of α-bromophenylacetic acid as a white solid, m.p. 73–83°. Recrystallization from about 400 ml. of ligroin (b.p. 90–120°) with 15 g. of decolorizing carbon affords 217–233 g. (60–62%) of the purified acid, m.p. 80.5–84°.

B. α,α'-Diphenylthiodiglycolic acid. In a 4-l. Erlenmeyer flask a suspension of 223 g. (1.04 moles) of α-bromophenylacetic acid in 1.25 l. of water is brought into solution by addition of a solution of 157 g. (1.48 moles) of sodium carbonate in 700 ml. of water. A solution of 104 g. (0.8 mole) of sodium sulfide (60–62% pure fused flakes) in 700 ml. of water is added, and the resulting mixture is stirred mechanically at room temperature for 3 hours, heated to the boiling point, filtered while hot, cooled, and cautiously acidified (in a hood) with 3 N hydrochloric acid. Filtration followed by washing with 200 ml. of water yields 135–140 g. (86–89%) of crude acid, m.p. 130–140°, which is sufficiently pure for use in the next step.

C. α,α'-Dibromodibenzyl sulfone. To a solution of 24.9 g. (0.0824 mole) of crude α,α'-diphenylthiodiglycolic acid in 250 ml. of glacial acetic acid contained in a 500-ml., three-necked, round-bottomed flask fitted with a bulb condenser is added 37.4 g. (0.33 mole) of 30% hydrogen peroxide over a 30-minute period, with ice bath cooling and magnetic stirring. The mixture is allowed to come to room temperature, and after 3 days 30 g. (0.19 mole) of bromine is added in one portion, followed by 30 g. of potassium bromide in 150 ml. of water. A sunlamp, focused on the reaction mixture from a distance of 1 in., causes the solution to warm to 80°. After heating at 80° for 30 minutes the mixture is cooled, and the solid is filtered and washed with water and ethanol, yielding 9–10 g. (27–30%) of crude α,α'-dibromodibenzyl sulfone, m.p. 135–150°. The mixture of diastereomers is pure enough to be used directly in the synthesis of 2,3-diphenylvinylene sulfone.