Reaction Steps
To a stirred suspension of NaH (60% dispersion in mineral oil, 1.69 g, 42 mmol) in THF (80 ml) under N2 was added dropwise diethylcarbonate (4.85 ml, 40 mmol) at room temperature, followed by 4-(3′,4′-dichlorophenyl)-3,4-dihydro-1-(2H)-naphthalone 1 (5.82 g, 20 mmol) in THF (20 ml). The mixture was refluxed for 48 hours, then cooled to 0° C. Acetic acid (10 ml) was added dropwise, and the mixture was extracted with Et2O. The Et2O extracts were washed with saturated NaHCO3 solution, brine, dried over MgSO4, and evaporated. The residue was purified by chromatography, CombiFlash silica gel column (hexane:CH2Cl2=50:50) to give Compound 9 as a clear oil (5.81 g, 80%). 1H NMR (CDCl3) δ 1.30 (t, J=7.2 Hz, 3H), 2.77 (dd, J=16 Hz, 9.6 Hz, 1H), 2.91 (dd, J=15.6 Hz, 6.4 Hz, 1H), 4.10 (dd, J=12 Hz, 6.4 Hz, 1H), 4.19-4.30 (m, 2H), 6.87 (d, J=6.8 Hz, 1H), 7.00 (dd, J=8.4 Hz, 2.0 Hz, 1H), 7.27-7.36 (m, 5H), 7.89 (dd, J=8.4 Hz, 2.0 Hz, 1H), 12.50 (s, 1H). 13C NMR (CDCl3) δ 14.5, 29.1, 43.4, 61.0, 95.6, 125.0, 127.6, 127.9, 128.1, 130.2, 130.6, 130.7, 131.0, 131.3, 132.8, 140.4, 143.9, 164.8, 172.6.
