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

Participants

Reaction Conditions

Reaction Steps

1-(5-bromo-2-(2-bromoethoxy)phenyl)ethanone from step H (9.0 g, 28.0 mmol) was dissolved in THF (175 mL), cooled to 0° C. and treated with sodium hydride (0.805 g, 33.5 mmol). The reaction mixture was carefully heated to reflux and continued heating for 20 h. The crude mixture was cooled, quenched with 2 M HCl (50 mL) and partitioned between brine (300 mL) and EtOAc (250 mL). The organic layer was dried over sodium sulfate, concentrated in vacuo and purified by silica gel column chromatography (10-30% EtOAc/hexanes). The clean fractions were concentrated in vacuo to afford 7-bromo-3,4-dihydrobenzo[b]oxepin-5(2H)-one (5.41 g, 22.4 mmol, 80% yield) as a colorless oil. LCMS (M+H)+=242.95. 1H NMR (500 MHz, chloroform-d) δ 7.91-7.85 (m, 1H), 7.54-7.48 (m, 1H), 6.98 (d, J=8.5 Hz, 1H), 4.25 (t, J=6.6 Hz, 2H), 2.91 (t, J=6.9 Hz, 2H), 2.23 (quin, J=6.8 Hz, 2H).

Provenance & Evidence