Water → 1-(5-Bromo-3,3,6-trimethyl-2,3-dihydro-benzofuran-7-yl)-ethanone

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Reaction Steps

A stirred, cooled (ice-bath) suspension of aluminum chloride (6.85 g, 51.4 mmol) in 50 mL of anhydrous dichloromethane was treated with acetyl chloride (3.7 mL, 51.4 mmol) under argon. A solution of 5-bromo-3,3,3-trimethyl-2,3-dihydro-benzofuran (Compound 47, 5.2 5 g, 25.7 mmol)in 10 mL of anhydrous dichloromethane was cannulated into the clear solution, and the resulting deep red solution was allowed to warm to ambient temperature over 1 hour. The reaction mixture was poured onto iced water and extracted with dichloromethane. The combined organic extract was dried over anhydrous sodium sulfate, filtered and evaporated to a dirty white solid. Flash column chromatography on silica gel using 6% ethyl acetate in hexane as the eluent afforded the title compound (4.5 g, 61.6%). 1H NMR (300 MHz, CDCl3): δ 7.30 (s, 1H), 4.28 (s, 2H), 2.56 (s, 3H), 2.34 (s, 3H), 1.33 (s, 6H).

Provenance & Evidence