Reaction Steps
The procedure for 48 was used with 56 (56 mg, 55 μmol) and 1N aqueous KOH (0.54 mL) to yield 57, which was used without further purification: IR (CHCl3) 2956, 2929, 2857, 1693, 1634, 1471, 1462, 1254, 1082, 836, 773 cm−1; 1H NMR (300 MHz, CDCl3) δ 7.34 (dd, J=15.1, 11.4 Hz, 1H), 6.64 (ddd, J=16.5, 10.6, 10.5 Hz, 1H), 6.61 (t, J=11.2 Hz, 1H), 6.07 (t, J=11.0 Hz, 1H), 6.01 (dd, J=15.5, 7.2 Hz, 1H), 5.58 (d, J=11.3 Hz, 1H), 5.44-5.34 (m, 2H), 5.23 (dd, J=11.0, 8.2 Hz, 1H), 5.17 (d, J=18.0 Hz, 1H), 5.08 (d, J=10.1 Hz, 1H), 4.50 (m, 1H), 3.92 (m, 1H), 3.69 (m, 1H), 3.35 (m, 1H), 2.75 (m, 1H), 2.54 (m, 2H), 1.74-1.56 (m, 4H), 1.49-1.20 (m, 7H), 1.02 (d, J=6.8 Hz, 3H), 0.98 (d, J=7.2 Hz, 3H), 0.94 (d, J=7.0 Hz, 3H), 0.90-0.82 (m, 45H), 0.09-0.01 (m, 24H); 13C NMR (75 MHz, CDCl3) δ 171.1, 148.2, 147.4, 136.4, 132.7, 132.6, 129.6, 127.0, 117.4, 115.1, 79.8, 78.4, 74.2, 72.1, 66.5, 43.5, 42.6, 41.5, 36.0, 35.9, 35.8, 35.0, 31.9, 30.8, 29.7, 26.3, 26.0, 25.9, 20.4, 19.3, 18.5, 18.13, 18.08, 17.97, 17.4, 15.4, 13.7, 10.8, −3.0, −3.4, −3.7, −4.1, −4.2, −4.3, −4.4, −4.8; LRMS (ESI) 1029.8 [M+Na]+, 832.3, 758.3, 684.3, 610.2, 541.2; HRMS (ESI) calcd for C56H110O7Si4Na 1029.7226 [M+Na]+, found 1029.7255; [α]20D−6.5 (c 0.17, CHCl3).
