P-Chloroacetophenone → 4-Chloro-alpha-methylstyrene

Participants

Reaction Conditions

Reaction Steps

To a slurry of triphenylmethylphosphonium bromide (71.4 grams (g), 200 millimole (mmole)) in 500 milliliters (ml) dry tetrahydrofuran (THF) (distilled from sodium/benzophenone), were slowly added dropwise 129 ml (200 mmole) 1.55 molar (M) n-butyllithium in hexane. The reaction mixture was stirred for 30 minutes at -10° C. whereafter a solution of 30.92 g (200 mmol) 4-chloroacetophenone in 100 ml dry THF was slowly added dropwise. The reaction mixture was then stirred for one hour at -10° C., slowly warmed to ambient temperature (about 23° C.) and stirring continued overnight. The mixture was thereafter filtered and the solvent removed by distillation at atmospheric pressure. Distillation, using a water aspirator, yielded 16.5 g (54.2% yield) of p-chloro-α-methylstyrene, boiling point (bp) 82°-86° C.

Provenance & Evidence