Reaction Steps
A three-necked round bottom flask was charged with the product from Example 6 (59.0 g, 0.182 mol) followed by CH2Cl2 (1.18 L). The resulting suspension was stirred briefly before adding allyltrimethylsilane (58 ml, 0.364 mol) all at once at room temperature. The suspension was cooled to 0° C. under nitrogen and was treated with BF3OEt2 (46.3 ml, 0.364 mol) dropwise keeping the reaction temperature below 2° C. After complete addition, the mixture was stirred at 0° C. for ˜1 hour. The completion of the reaction was monitored with HPLC until the starting material was consumed. The reaction mixture was poured into saturated NaHCO3 solution and stirred for 30 minutes. The organic layer was separated, washed with brine, dried over Na2SO4, treated with charcoal, filtered and concentrated to an oil. EtOH (200 ml) was added and the solution was concentrated to give a crystalline solid which was suspended with heptane at 0° C. for 2 hours before filtration to give a solid which was dried under reduced pressure at 45° C. to provide the title compound as a light yellow crystalline solid (60.1 g, 95.1%). Anal. Calcd for C23H25NO2: C, 79.51; H, 7.25; N, 4.03; Found: C, 79.26; H, 7.12; N, 3.80, 1H NMR [(CD3)2SO] δ1.16 (3H, s) 1.17 (3H, s), 2.18 (3H, s), 2.22 (1H, m), 2.46 (1H, m), 3.85 (3H, s), 5.01 (2H, m), 5.44 (1H, br s), 5.77 (1H, dd), 5.82 (1H, m), 6.10 (1H, br s), 6.52 (1H, d), 6.60 (1H, d), 6.70 (1H, d), 7.06 (1H, t,), 7.96 (1H, d); 13C NMR [(CD3)2SO] δ23.8, 28.8, 28.9, 36.5, 49.7, 55.6, 73.4, 105.6, 110.5, 113.4, 113.4, 116.1, 116.4, 127.3, 117.3, 127.3, 127.7, 132.2, 133.8, 134.5, 145.8, 151.1, 156.4. MS (APCI) m/z: 348 (M+H)+.
