Reaction Steps
Following the procedure in the preparation of 11, compound 11′ was prepared from alcohol 10′ (2.010 g, 4.04 mmol) as a pale white foamy solid (2.599 g, 99% yield): [α]26D=−30.5 (c=1.04, MeOH); HPLC of 11′ for purity: 98.0%, [major peak: Rt=15.9 min; minor peaks: 19.0 min and 24.6 min; column: Chiralcel ODH (250×4.6 mm), UV detector, 210 nm, 5% 2-propanol in hexanes; flow rate: 1.0 mL/min]. 1HNMR (200 MHz, CD2Cl2) δ 7.72 (d, 2H, J=8.4 Hz), 7.28 (d, 2H, J=8.2 Hz), 6.73 (br s, 1H), 6.15 (s, 2H), 5.12 (br s, 1H), 4.84 (t, 1H, J=6.0 Hz), 4.39 (dd, 1H, J1=13.9 Hz, J2=5.7 Hz), 4.27 (dd, 1H, J1=13.9 Hz, J2=5.3 Hz), 3.96 (q, 1H, J=7.4 Hz), 3.821 (s, 3H), 3.817 (s, 6H), 2.41 (s, 3H), 2.20 (t, 2H, J=6.4 Hz), 1.43 (s, 9H), 1.42 (s, 9H). 13C NMR (50 MHz, CD2Cl2) δ 170.6, 167.1, 161.2, 159.4, 155.4, 145.5, 132.9, 130.1, 128.1, 106.1, 90.9, 82.1, 79.9, 77.5, 56.0, 55.5, 51.6, 34.8, 32.6, 28.4, 28.1, 21.8. HRMS calcd for C31H45N2O11S (M+H)+: 653.2744. found: 653.2740.
