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

Participants

Reaction Steps

To a stirred solution of 8-bromo-3,4-dihydro-2H-benzo[b]oxepin-5-one (3.10 g; 12.8 mmol) in Et2O at 0° C. was added Br2 (625 μl; 12.2 mmol) and the reaction mixture was allowed to warm to r.t. over 2 h. Volatiles were evaporated and the residue purified by flash column chromatography (0-20% EtOAc in hexanes) to give 4,8-dibromo-3,4-dihydrobenzo[b]oxepin-5(2H)-one as a colorless solid (4.0 g, 96% yield). 1H NMR (400 MHz, CDCl3) δ 7.18-7.21 (m, 2H), 7.55 (d, J=8.0, 1H), 4.87 (app. t, J=5.2, 2H), 4.33-4.39 (m, 1H), 4.09-4.16 (m, 1H), 2.78-2.91 (m, 1H), 2.40-2.49 (m, 1H).

Provenance & Evidence