Sodium hydride → 7-Bromo-3,4-dihydro-1-benzoxepin-5(2H)-one

Participants

Reaction Steps

To a slurry of NaH (60% dispersion in mineral oil) (1.48 g, 37.1 mmol) in THF (50 mL) at room temperature was added [5-bromo-2-(2-bromo-ethoxy)-phenyl]-ethanone (8.07 g, 25.1 mmol). The reaction mixture was slowly heated to reflux and allowed to stir for 20 h. The solvent was removed in vacuo and the residue subjected to flash chromatography (SiO2, 4:1 ethyl acetate/petroleum ether) to give 7-Bromo-3,4-dihydro-2H-benzo[b]oxepin-5-one as a yellow oil (4.22 g, 70%). 1H NMR (CDCl3) δ 2.15-2.29 (2H, m), 2.89 (2H, t, J=7.0 Hz), 4.24 (2H, t, J=6.6 Hz), 6.97 (1H, d, J=8.8 Hz), 7.50 (1H, dd, J=2.6, 8.1 Hz), 7.87 (1H, d, J=2.6 Hz).

Provenance & Evidence