1,3-Cyclohexanedione → 7-bromo-3,4-dihydrodibenzo[b,d]furan-1(2H)-one

Participants

Reaction Conditions

Reaction Steps

A mixture of the product of Example 60, step B (9.0 g, 40.1 mmol) and cyclohexane-1,3-dione (6.74 g, 60.1 mmol) in 10% H2SO4/acetic acid (100 mL) was heated at 110° C. for 12 h. After cooling to ambient temperature, the reaction mixture was diluted with water, basified by treating with 10 N NaOH and extracted with dichloromethane. The organic layer was washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to give the crude material which was purified by flash column chromatography (SiO2, 90:10 hexanes/ethyl acetate) to provide 7-bromo-3,4-dihydrodibenzo[b,d]furan-1(2H)-one (6.8 g, 64%) as a pale yellow solid: 1H NMR (CDCl3, 300 MHz) δ 7.91 (d, J=8.1 Hz, 1H), 7.65 (d, J=1.5 Hz, 1H), 7.45 (dd, J=8.1, 1.5 Hz, 1H), 3.03 (t, J=6.3 Hz, 2H), 2.61 (t, J=6.3 Hz, 2H), 2.35-2.24 (m, 2H).

Provenance & Evidence