Hydrogen Bromide → 2-Bromo-1-(oxan-4-yl)ethan-1-one

Participants

Reaction Steps

Thionyl chloride (2 mL, 27 mmol) was added to tetrahydro-pyran-4-carboxylic acid (1.1 g, 8.4 mmol) at 10° C. The mixture was warmed to ambient temperature and stirred for 2 h. Excess thionyl chloride was evaporated and the residue co-distilled with toluene to remove the traces of thionyl chloride. The resulting crude acid chloride was dissolved in dry acetonitrile (3 mL) and cooled to 0° C. Trimethylsilyl diazomethane (12.6 mL, 25.3 mmol) was added and the reaction mixture was stirred at ambient temperature for 2 h. It was then cooled to −10° C. and a solution of 15% HBr in acetic acid (2 mL) was added. The mixture was stirred at room temperature for 1 h then quenched with saturated sodium bicarbonate solution and extracted with ether (3×20 mL). The combined ether extracts were washed with brine, dried over anhydrous sodium sulfate and concentrated in vacuo to afford 2-bromo-1-(tetrahydro-pyran-4-yl)-ethanone (620 mg, 35%) as an oil.

Provenance & Evidence