To a solution of the product from Example 7D (200 mg, 0.65 mmole) in dichloromethane (10 mL) at room temperature, was added triethylamine (750 μL) followed by acetic anhydride (300 μL, 3.2 mmole) and 4-(dimethylamino)pyridine (5 mg). The reaction mixture was stirred at room temperature, overnight and quenched with methanol for an hour. The solvent was evaporated in vacuum and the product was purified via silica column, using a gradient of 5-20% ethyl acetate in hexane. Yield of the clear oil, 165 mg (72.5%). 1H NMR (300 MHz, CDCl3) δ ppm 1.35 (d, J=6.25 Hz, 6H) 1.35 (d, J=6.62 Hz, 3H) 2.06 (s, 3H) 4.40-4.63 (m, 1H) 5.35-5.50 (m, 1H) 5.73 (dd, J=15.81, 6.62 Hz, 1H) 6.57 (d, J=15.81 Hz, 1H) 6.84-6.96 (m, 2H) 7.07 (s, 1H) 7.12-7.22 (m, 2 H). Mass spectrum DCI 348 (M+H)+.
