3'-Bromoacetophenone → 1-Bromo-3-(prop-1-en-2-yl)benzene

Participants

Reaction Conditions

Reaction Steps

Methyltriphenylphosphonium bromide (35.7 g, 97.9 mmoles, 1.3 equiv) is suspended in tetrahydrofuran (100 mL) and cooled to 0° C. N-Butyllithium (2.5M in hexanes, 27.0 g, 97.7 mmoles, 39.2 mL, 1.3 equiv) is added slowly to the mixture via an addition funnel. The resulting solution is stirred for 1 h at 0° C. A solution of 3-bromoacetophenone (15.0 g, 75.3 mmoles, 10.0 mL, 1.0 equiv) in tetrahydrofuran (50 mL) is added slowly via an addition funnel. The resulting mixture is warmed to room temperature and stirred for 3 h. The reaction is cooled to 0° C. and quenched with saturated aqueous ammonium chloride solution. The layers are partitioned in a separatory funnel and the aqueous phase is extracted with hexanes. The combined organic phase is dried over anhydrous sodium sulfate, filtered, and allowed to stand overnight at room temperature. The organic phase is decanted from a precipitate and concentrated under reduced pressure. The resulting solid is diluted with hexanes and filtered. The precipitate is washed with hexanes. The filtrate is concentrated and the resulting mixture is purified by silica gel flash column chromatography (hexanes) to give the title compound (83% yield): 1H NMR (CDCl3, 400 MHz) δ 7.59 (t, 1H, J=1.72 Hz), 7.40-7.36 (m, 2H), 7.18 (t, 1H, J=8 Hz), 5.36 (s, 1H), 5.12-5.10 (m, 1H), 2.13-3.11 (m, 3H).

Provenance & Evidence