Acetyl chloride → 8-Acetyl-6-bromo-2,2,4,4-tetramethyl chroman

Participants

Reaction Steps

A stirred, cooled (ice bath) suspension of aluminum chloride (0.99 g, 7.46 mmol) in anhydrous dichloromethane (20 mL) was treated with acetyl chloride (0.58 g, 7.46 mmol). After 5 minutes, a solution of 6-bromo-2,2,4,4-tetramethyl chroman (1 g, 3.73 mmol)in dichloromethane was added. The reaction was allowed to warm to ambient temperature and stirred for 2 h. The reaction mixture was then poured into ice containing 10% hydrochloric acid and extracted with diethyl ether (×2). The combined organic phase was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous sodium sulfate, filtered and evaporated in vacuo to a residue which was subjected to flash column chromatography over silica gel (230-400 mesh) using 5% ethyl acetate in hexane as the eluent to afford the title compound as a pale yellow oil (0.95 g, 83%). It was used as such for the next step without any characterization.

Provenance & Evidence