Benzyltriphenylphosphonium bromide → 1-(4-Methoxy-benzenesulfonyl)-3-styryl-azepane-2-carboxylic acid tert-butyl ester

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Reaction Steps

To a solution of Benzyl triphenylphosphonium bromide (229 mg, 0.528 mmoL) in 2 mL of THF at 0° C. was added 2.0M butyl lithium solution (0.272 mL) in pentane. After five minutes the solution was warmed to ambient temperature, and kept at that temperature for 30 minutes before adding in the 3-Formyl-1-(4-methoxy-benzene sulfonyl)-azepane-2-carboxylic acid tert-butyl ester (200 mg, 0.503 mmoL) dissolved in 1.52 mL of THF. After 20 hours the reaction was quenched by adding water dropwise, the reaction was diluted with ethyl acetate and washed twice with brine. The organic layer was dried over anhydrous magnesium sulfate, filtered, and the solvent evaporated under reduced pressure. The residue was purified by column chromatography (silica: 20% to 25% ethyl acetate in hexanes) to yield 1-(4-Methoxy-benzenesulfonyl)-3-styryl-azepane-2-carboxylic acid tert-butyl ester; MS: (M+H)+ =472, (M+NH4)+ =489.

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