Potassium Carbonate → 2-(4-Bromophenyl)naphthalene

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Reaction Conditions

Reaction Steps

First, into a 200-mL three-neck flask were placed 9.7 g of 4-bromoiodobenzene, 3.1 g of 2-naphthylboronic acid, and 0.35 g of tri(ortho-tolyl)phosphine (P(o-tolyl)3), to which 30 mL of toluene, 6 mL of ethanol, and 10 mL of a 2.0M aqueous potassium carbonate solution were added. The mixture in this flask was degassed under reduced pressure, and the air in the flask was replaced with nitrogen. To this mixture was added 0.037 g of palladium(II) acetate, and the mixture was refluxed under a nitrogen stream at 90° C. for 6 hours. After the reflux, organic substances were extracted from the aqueous layer of this mixture with toluene. The solution of the extract was combined with the organic layer of the mixture. The resulting mixture was washed with a saturated aqueous solution of sodium hydrogen carbonate and then saturated brine. After the washing, anhydrous magnesium sulfate was added for drying. The obtained mixture was separated by gravity filtration, and the filtrate was concentrated to give a solid. The obtained solid was purified by silica gel column chromatography. In the column chromatography, hexane was first used as a developing solvent, and then a mixed solvent in which a hexane/ethyl acetate ratio was 20:1 (v/v) was used. The obtained fractions were concentrated to give a solid. The obtained solid was recrystallized using a mixed solvent of toluene and hexane to give 2-(4-bromophenyl)naphthalene (as a white solid in 61% yield). The synthesis scheme of Step (a-2) is illustrated below.

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