p-Bromoacetophenone → 1-[4-[(E)-2-phenylethenyl]phenyl]ethanone

Participants

Reaction Steps

An oven dried Schlenk flask was charged with Pd(OAc)2 (2.2 mg, 0.01 mmol, 1 mol %) and tethered ligand 2 (45.8 mg, 0.0044 mmol, 0.44 mol %). The flask was evacuated and backfilled with nitrogen and then capped with a rubber septum. Dry dimethylformamide (5 ml) was added and the mixture was stirred for 60 min at room temperature under nitrogen. 4′-Bromoacetophenone (0.199 g, 1.0 mmol), styrene (0.137 ml, 1.2 mmol), and triethylamine (0.195 ml, 1.4 mmol) were added successively. The rubber septum was replaced with a glas stopper, the flask was sealed, and the mixture was stirred at 120° C. for 20 h. After cooling to room temperature, the mixture was filtered, and the solid was washed with methyl-t-butyl ether (MTBE), water, MeOH, acetone, and once more with MTBE. The phases of the filtrate were separated and the aqueous phase was extracted with MTBE (2×30 ml). The combined organic extracts were dried over MgSO4 and concentrated under reduced pressure. The crude product was purified by flash chromatography on silica gel (hexane/EtOAc, 10/1 to 1/1) to give E-4-acetylstilbene (0.192 g, 86%) as a white solid.

Provenance & Evidence