Aluminum(III) Chloride → ethyl 9-bromo-7-chloro-4,5-dihydro-3H-benzofuro[2,3-d]azepine-3-carboxylate

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Reaction Steps

To a stirred solution of the product of step B (660 mg, 1.52 mmol) in anhydrous dichloromethane (8 mL) at 0° C. was added AlCl3 (810 mg, 6.07 mmol) and the reaction mixture was allowed to warm to ambient temperature over 3 h before being quenched by addition of aqueous sodium bicarbonate solution. The organic layer was separated and the aqueous solution further extracted with dichloromethane (2×20 mL). The combined organic extracts were dried over anhydrous Na2SO4, filtered and the filtrate concentrated in vacuo. The residue was purified by flash column chromatography (SiO2, 9:1 to 1:1 hexanes/ethyl acetate) to give ethyl 9-bromo-7-chloro-4,5-dihydro-3H-benzofuro[2,3-d]azepine-3-carboxylate (50 mg, 9%) as an off-white solid: 1H NMR (CDCl3, 300 MHz) δ 7.56 (d, J=1.7 Hz, 1H), 7.39 (d, J=1.6 Hz, 1H), 7.08-6.82 (m, 1H), 5.88-5.70 (m, 1H), 4.38 (q, J=7.1 Hz, 2H), 3.90 (t, J=5.1 Hz, 2H), 3.26 (t, J=5.0 Hz, 2H), 1.34 (t, J=7.0 Hz, 3H).

Provenance & Evidence