Tributylvinyltin → 4-(Ethenyl)-2-[(4-chlorophenoxy)methyl]-1-trifluoromethanesulfonylbenzimidazole

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Reaction Steps

To a 250 ml round bottom flask were added 4-trifluoromethanesulfonyloxy-2-[(4-chlorophenoxy)methyl]-1-trifluoromethanesulfonylbenzimidazole (5.00 g, 9.28 mmol), palladium tetrakis(triphenylphosphine) (428 mg, 0.371 mmol), lithium chloride (2.95 g, 69.6 mmol) and vinyltributyltin (2.94 g, 9.28 mmol) to anhydrous tetrahydrofuran. The reaction mixture was heated to reflux and maintained at this temperature overnight. The progress of the reaction was monitored by thin layer chromatography. An additional 428 mg of the palladium catalyst was added and the resulting mixture was refluxed an additional three hours. To the reaction mixture was added cuprous iodide (35.3 mg, 0.02 eq) and the reaction mixture was refluxed overnight. The solvents were removed in vacuo. The residue was redissolved in ethyl acetate (500 ml) and was washed with 1:1 water:28% aqueous ammonium hydroxide (3×). The organic fraction was dried over sodium sulfate. The desired title product was further purified by column chromatography.

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