Reaction Steps
To a solution of 21 (4.63 g, 12.38 mmol) in dichloromethane (62 mL) was added acetic anhydride (1.40 mL, 14.9 mmol), triethylamine (2.61 mL, 18.6 mmol), and a catalytic amount of N,N-dimethylaminopyridine. The solution was stirred for 30 minutes at room temperature, diluted with dichloromethane (60 mL), washed with water (100 mL) and 5% HCl solution (100 mL). The organic layer was washed with a saturated NaHCO3 solution (100 mL), dried over MgSO4, and concentrated to give a light yellow oil. To a heterogeneous mixture of HgCl2(6.72 g, 24.8 mmol) and sodium iodide (5.53 g, 37.1 mmol) in acetonitrile (180 mL) was added chlorotrimethylsilane (4.71 mL, 37.1 mmol) at room temperature, followed by the addition of water (0.67 mL, 37.1 mmol). After 5 min, a solution of acetylated compound of 21 in acetonitrile (120 mL) was added. The reaction was allowed to stir at room temperature for 16 h. The contents of the reaction were filtered through a pad of celite. The filtrate was treated with water (500 mL) and the product extracted with diethyl ether. The combined organic extracts were washed with brine, dried over MgSO4, and concentrated. The product was purified via flash column chromatography using silica gel to give 41 (3.41 g, 85%). 1H NMR (300 MHz, CDCl3) δ 7.89 (d, J=7.2 Hz, 2H), 7.69 (t, J=7.5 Hz, 1H), 7.59 (t, J=7.2 Hz, 2H), 4.84 (m, 1H), 3.51 (dd, J=12.9 Hz, 4.2 Hz, 1H), 3.00 (m, 1H), 2.88 (dd, J=17.7 Hz, 12.9 Hz, 1H), 2.67 (dd, J=17.7, 4.5 Hz, 1H), 2.41 (m, 2H), 2.02 (s, 3H), 1.90 (m, 1H), 1.71 (m, 1H), 1.00 (d, J=7.2 Hz, 3H); 13C NMR (75 MHz, CDCl3) δ 207.0, 169.6, 137.0, 134.2, 129.5, 128.7, 75.8, 60.8, 38.9, 33.9, 24.6, 21.0, 7.3; LRMS (CI) m/z 325 (M+H), 265 (M+H-AcOH).
