反应详情

A solution of 7-bromo-2-tetralone (1.1 g, 4.9 mmol), ethylene glycol (0.62 g, 10 mmol), and p-toluensulfonic acid (80 mg, 0.42 mmol) in benzene (20 ml) was stirred under N2 at reflux utilizing a Dean-Stark trap for 45 minutes. The cooled solution was diluted with diethyl ether (60 ml), washed with saturated NaHCO3 solution (2×10 ml), dried (MgSO4) and concentrated in vacuo to give 7'-bromo-3',4'-dihydrospiro[1,3-dioxolane-2,2'(1'H)-naphthalene] as an oil (1.2 g). 1H NMR (CDCl3, 200 MHz) δ: 1.95 (t, J=7 Hz, 2H, CH2), 2.91 (t, J=7 Hz, 2H, CH2), 2.95 (s, 2H, CH2), 4.01 (s, 4H, OCH2CH2O), 6.97 (d, J=8 Hz, 1H, Ar), 7.15-7.27 (m, 2H, Ar).

1. temperatureat reflux
2. customfor 45 minutes
3. washwashed with saturated NaHCO3 solution (2×10 ml)
4. dry with materialdried (MgSO4)
5. concentrationconcentrated in vacuo