Imidazole → Triphenylphosphine Oxide

Participants

Reaction Steps

To a 250 mL flask in an ice bath was added triphenyl phosphine (6.17 g, 22.8 mmol), imidazole (1.6 g, 22.8 mmol) and 100 mL of anhydrous dichloromethane. Once dissolved, iodine (5.79 g, 22.8 mmol) was added. The reaction was then stirred for about 30 minutes (ppt formed). The 2-(4-bromo-2-methylphenyl)ethanol (3.93 g, 18.3 mmol) was added in batches and the flask was rinsed with the remaining DCM (22 mL) which was also added to the reaction mixture. The reaction was warmed to room temperature and was stirred overnight. The reaction mixture was filtered through a small pad of celite and washed with DCM (100 mL). The filtrate was washed with saturated aqueous sodium thiosulfate (200 mL) and brine 200 mL. The organics were concentrated in vacuo to furnish a white solid (triphenyphosphine oxide+desired product). The material was triturated with heptanes for 5-10 mins then filtered to remove the majority of the triphenylphosphine oxide The filtrate was concentrated in vacuo to furnish a total of 5.86 g (98.8%) of the title compound as a clear oil that solidified upon standing. 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 2.30 (s, 3H) 3.04-3.20 (m, 2H) 3.21-3.39 (m, 2H) 7.02 (d, J=8.20 Hz, 1H) 7.23-7.29 (m, 1H) 7.30-7.38 (m, 1H).

Provenance & Evidence