To a solution of the product of Example 7F (85 mg, 0.26 mmole) in tetrahydrofuran (3 mL)) was added triphenylphosphine (75 mg, 0.29 mmole) and stirred at 50° C. for 3.5 hours. The reaction mixture was added an aqueous solution of 2N NaOH (0.3 mL) and stirring was continued at 50° C. for additional 40 minutes. The reaction mixture was cooled down to room temperature, added acetic anhydride (200 μL, 2.1 mmole), stirred for 45 minutes, quenched with methanol and stirred at room temperature, overnight. The reaction mixture was diluted with methylene chloride and washed with water (×3) and brine. The product was purified via silica column, using a gradient of 25-100% ethyl acetate in hexane and yielded 40 mg (44.9%) of light yellow oil. 1H NMR (300 MHz, CDCl3) δ ppm 7.11-7.22 (m, 2H) 7.04 (s, 1H) 6.85-6.95 (m, 2H) 6.48 (dd, J=15.44, 1.10 Hz, 1H) 5.72 (dd, J=15.63, 5.70 Hz, 1H) 5.37 (d, J=8.46 Hz, 1H) 4.60-4.76 (m, 1H) 4.44-4.59 (m, 1H) 2.00 (s, 3H) 1.34 (d, J=6.25 Hz, 6H) 1.28 (d, J=6.62 Hz, 3H). Mass spectrum DCI 347 (M+H)+.
