Bromine → 4,8-dibromo-3,4-dihydrobenzo[b]oxepin-5(2H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of 8-bromo-3,4-dihydro-2H-benzo[b]oxepin-5-one (1.2 g, 5 mmol) in diethyl ether (20 mL) at 0° C. was added bromine (257 μL, 5 mmol) dropwise under nitrogen. The reaction mixture was stirred at 0° C. for 1 h, allowed to warm up to RT and stirred for 3 h. Further bromine (50 μL, 0.97 mmol) was added and stirring was pursued for 16 h. The solvent was removed in vacuo and the resultant residue was purified by flash chromatography (SiO2, 10% ethyl acetate in cyclohexane) to give the title compound as a white solid (1.55 g, 97%). 1H NMR (CDCl3): 7.62 (1H, m), 7.26 (2H, m), 4.94 (1H, dd, J=7.7, 6.7 Hz), 4.43 (1H, ddd, J=12.7, 5.6, 4.8 Hz), 4.25-4.15 (1H, m), 2.97-2.86 (1H, m), 2.51 (1H, ddt, J=14.7, 7.7, 4.6 Hz).

Provenance & Evidence