Reaction Steps
The ester 46 (81 mg, 71 μmol) was added to CH2Cl2 (2 mL) and H2O (0.1 mL) and DDQ (20 mg, 88 μmol) was added at 0° C. After 1 h of stirring at 0° C., the reaction mixture was quenched by adding saturated aqueous NaHCO3 (5 mL). The organic phase was washed with saturated aqueous NaHCO3 (3×10 mL) and brine, dried over MgSO4, filtered and concentrated. Purification by flash column chromatography (EtOAc/hexane 1:9) furnished 47 (64 mg, 88%) as a colorless oil: IR (CHCl3) 3541, 2956, 2929, 2856, 1722, 1639, 1471, 1462, 1377, 1360, 1254, 1175, 1086, 836, 773 cm−1; 1H NMR (300 MHz, CDCl3) δ 7.34 (dd, J=15.4, 11.2 Hz, 1H), 6.61 (ddd, J=16.8, 10.7, 10.6 Hz, 1H), 6.51 (t, J=11.3 Hz, 1H), 6.06 (t, J=11.0 Hz, 1H), 5.96 (dd, J=15.4, 7.1 Hz, 1H), 5.56 (d, J=11.3 Hz, 1H), 5.39 (t, J=10.1 Hz, 1H), 5.38 (t, J=10.3 Hz, 1H), 5.22 (dd, J=11.0, 8.5 Hz, 1H), 5.17 (d, J=18.7 Hz, 1H), 5.09 (d, J=10.1 Hz, 1H), 4.50 (m, 1H), 3.92 (m, 1H), 3.71 (m, 1H), 3.70 (s, 3H), 3.44 (m, 1H), 3.32 (m, 1H), 2.74 (m, 1H), 2.52 (m, 2H), 2.31 (br, 1H), 1.61 (m, 4H), 1.39 (m, 2H), 1.31 (m, 2H), 1.26 (m, 3H), 1.00 (d, J=6.7 Hz, 3H), 0.93 (d, J=6.9 Hz, 3H), 0.92 (d, J=6.7 Hz, 3H), 0.86 (m, 27H), 0.84 (m, 6H), 0.82 (m, 12H), 0.05 (s, 9H), 0.02 (s, 3H), 0.01 (s, 6H), 0.00 (s, 6H); 13C NMR (75 MHz, CDCl3) δ 166.8, 147.3, 145.5, 135.3, 132.7, 132.6, 132.3, 129.9, 126.8, 117.7, 115.5, 79.9, 77.6, 76.6, 72.1, 66.5, 51.0, 43.5, 42.4, 41.5, 37.7, 36.1, 35.7, 35.0, 32.1, 31.5, 30.6, 26.3, 25.9, 25.9, 20.4, 19.4, 18.5, 18.1, 17.9, 17.7, 15.3, 13.3, 6.9, −3.0, −3.4, −3.7, −4.1, −4.2, −4.4; LRMS (ESI) 1043.6 [M+Na]+, 889.6, 757.5, 625.4, 393.3; HRMS (ESI) calcd for C57H112O7Si4Na 1043.7383 [M+Na]+, found 1043.7417; [α]20D−25.3 (c 0.61, CHCl3).
