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

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[Cl-].[Al+3].[Cl-].[Cl-].[C:5](Cl)(=[O:7])[CH3:6].[Br:9][C:10]1[CH:11]=[C:12]2[C:17](=[CH:18][CH:19]=1)[O:16][C:15]([CH3:21])([CH3:20])[CH2:14][C:13]2([CH3:23])[CH3:22]>ClCCl>[C:5]([C:18]1[CH:19]=[C:10]([Br:9])[CH:11]=[C:12]2[C:17]=1[O:16][C:15]([CH3:20])([CH3:21])[CH2:14][C:13]2([CH3:23])[CH3:22])(=[O:7])[CH3:6]

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실험 절차

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.