2-Bromo-1-(2,2-dimethyl-4H-benzo[d][1,3]dioxin-6-yl)ethanone

Synthesis

At about -78° C., sodium bis(trimethylsilyl)amide in tetrahydrofuran (1.0M) (2.9 mL) was added to a solution of 1-(2,2-dimethyl-4H-benzo[d][1,3]dioxin-6-yl)ethanone (500 mg; 2.43 mmol; 1.00 equiv) in tetrahydrofuran (20 mL). The solution was stirred at about -78° C. for about 1 hour, and chlorotrimethylsilane (290 mg, 2.64 mmol, 1.09 equiv, 99%) was added. The solution was stirred at about -78° C. for about 30 min, and then bromine (390 mg; 2.41 mmol; 0.99 equiv) was added. The solution was stirred at about -78° C. for about 1 hour, and then an aqueous solution of 5% sodium sulfite and 5% sodium bicarbonate (50 mL) was added. Following standard extractive workup with ethyl acetate, the crude residue was then purified by silica gel column chromotagraphy with ethyl acetate/petroleum ether (1/12) to give the title product as a pale yellow oil 2-Bromo-1-(2,2-dimethyl-4H-benzo[d][1,3]dioxin-6-yl)ethanone (400 mg; 57% yield).