Reaction Steps
A solution of 5 (100 mg, 0.19 mmol) in CH2Cl2 (10 mL) was cooled to −78° C., to which O3 was charged until the reaction solution turned purple (˜10 min). The O3 flow was stopped, and the reaction was allowed to stir at the same temperature for 30 min. To the resulting solution was added Me2S (150 μL). The reaction mixture was then warmed to room temperature and kept stirring at room temperature for an additional 2 h. The solvent was removed by rotary evaporation and the resulting crude product was purified by flash column chromatography (EtOAc/hexanes, 1:1, Rf=0.2) to yield 6 (87 mg, 87%) as a colorless oil: 1H NMR (500 MHz, CDCl3) δ 1.45 (s, 27H), 2.22 (s, 3H), 2.70-2.85 (m, 111), 2.85-2.95 (m, 1H), 3.05-3.15 (m, 1H), 3.16-3.25 (m, 1H), 3.30-3.37 (m, 1H), 3.45-3.70 (m, 2H), 3.85-3.95 (m, 2H), 4.05-4.20 (t, J=10.0 Hz, 1H), 6.90-6.93 (m, 2H), 9.66 (s, −1H); 13C NMR (125 MHz, CDCl3) δ 20.9, 24.7, 27.9, 28.5, 29.7, 34.4, 42.5, 43.2, 48.8, 49.1, 50.3, 51.0, 74.6, 74.9, 79.4, 79.5, 80.4, 83.0, 119.66, 119.73, 122.8, 149.7, 149.8, 151.57, 151.60, 151.8, 154.4, 154.8, 159.87, 158.94, 200.2, 200.6; LC-TOF (M+H+) calcd for C28H44N3O8 550.3128. found 550.3130.
