[(4-Bromophenyl)methyl]triphenylphosphanium bromide → Methyl 4-(1-(4-bromophenyl)-4-methylpent-1-en-2-yl)benzoate

Participants

Reaction Conditions

Reaction Steps

4-Bromobenzyltriphenylphosphonium bromide (2.07 g, 4.40 mmol) was suspended in toluene (4.0 mL) and cooled to 0° C. Lithium bis(trimethylsilyl)amide (4.04 mL, 1.0 M in toluene) was added. The ice bath was removed and the reaction was allowed to warm to room temperature and stir for 1 hour. A solution of Intermediate (10) (180 mg, 0.817 mmol) in toluene (0.8 mL) was then added drop-wise, and the reaction was allowed to stir for 18 hours. The reaction was diluted with water and ethyl acetate. The layers were separated and the aqueous was extracted three times with ethyl acetate. The combined organics were washed twice with 1N HCl and once with brine, then dried over magnesium sulfate, filtered, and concentrated. The crude solid was taken up in heptane and the remaining solids (triphenylphospine oxide) were filtered off. The filtrate was concentrated and purified by column chromatography (0-10% ethyl acetate in heptane) to give methyl 4-(1-(4-bromophenyl)-4-methylpent-1-en-2-yl)benzoate (184.7 mg, 61%) as an approximate 1:1 mixture of E/Z isomers. 1H NMR (400 MHz, CDCl3, δ): 8.04-8.00 (m, 2H), 7.97-7.92 (m, 2H), 7.50-7.46 (m, 4H), 7.22-7.16 (m, 6H), 6.77-6.72 (m, 2H), 6.69 (s, 1H), 6.39 (s, 1H), 3.92 (s, 3H), 3.90 (s, 3H), 2.58 (d, J=7.4 Hz, 2H), 2.37 (dd, J=7.2, 1.2 Hz, 2H), 1.68-1.57 (m, 1H), 1.51 (dt, J=13.5, 6.8 Hz, 1H), 0.88 (d, J=6.6 Hz, 6H), 0.78 (d, J=6.6 Hz, 6H).

Provenance & Evidence