Propargyl alcohol → 3-(4-Chlorophenyl)prop-2-yn-1-ol

Participants

Reaction Steps

A suspension of p-iodochlorobenzene [formula (VII), 7.15 g, 30.0 mmol], propargyl alcohol (1.75 mL, 30 mmol), dichlorobis(triphenylphosphine)palladium (II) (0.21 g, 0.3 mmol), copper (I) iodide (29 mg, 0.15 mmol) and diethylamine (50 mL) was stirred under a N2 atmosphere at room temperature and dissolution occurred within 20 min. After 5 h, the diethylamine was removed, and the crude product was partitioned between water and ether. The ether phase was dried (brine), concentrated and flash chromatographed (4:1 petroleum ether: ethyl acetate) to provide 3-(4-chlorophenyl)-prop-2-yn-ol (compound of formula VIII, 4.09 g, 82%). This compound of formula (VIII) (3.47 g, 20.83 mmol) was suspended in dry ether (12 mL) and pyridine (0.42 mL) was added. The reaction mixture was cooled in an ice bath and a solution of phosphorus tribromide (1.0 mL, 10.42 mmol) in dry ether (6 mL) was added dropwise over a 15 min period. The reaction mixture was then stirred at room temperature for 2.5 h, cooled in an ice bath and crushed ice was added. The reaction mixture was added to water (200 mL) and extracted with ether (200 mL). The ether phase was washed with water, sat. aqueous NaHCO3 and brine. The extract was concentrated and flash chromatographed (9:1 petroleum ether:ethyl acetate) to provide the product as a white solid (3.38 g, 86%): mp 41°-43° C.; NMR (CDCl3): δ7.37 (d, J=8.7 Hz, 2H, ArH), 7.27 (d, J=8.7 Hz, 2H, ArH), 4.16 (s, 2H, CH2).

Provenance & Evidence