A solution of potassium tert-butoxide (1.0 M in tetrahydrofuran, 0.70 mL, 0.70 mmol) was added dropwise via syringe to a suspension of the product of Example 68C (147 mg, 0.587 mmol) in anhydrous tetrahydrofuran (5 mL) at ambient temperature. The reaction mixture was stirred for 45 minutes, and then a solution of the product of Example 166B (273 mg, 0.587 mmol) in 3 mL tetrahydrofuran was added. The reaction was allowed to proceed for 1 hour at ambient temperature, then poured into brine. The product was extracted with ethyl acetate and the combined organic layer was washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. The crude product was purified by chromatography on silica gel (Analogix® Intelliflash™ 280; SF15-24 g column; 25%-75% ethyl acetate/hexanes, 0-15 minutes, 30 mL/minute) to afford the title compound. 1H NMR (300 MHz, CDCl3) δ ppm 7.69 (d, J=8.3, 2H), 7.35 (d, J=8.2, 2H), 7.32-7.15 (m, 10H), 4.86-4.72 (m, 1H), 4.24-4.05 (m, 2H), 3.67 (bs, 2H), 3.45 (t, J=6.3, 2H), 2.80 (t, J=12.6, 2H), 2.67-2.55 (m, 2H), 1.90-1.73 (m, 4H), 1.39 (s, 9H), 1.29-1.11 (m, 2H); MS (DCI+) m/z 636 (M+H)+.
