Reaction Steps
ZnBr2 (0.41 g) in 1.2 mL of 5:1 CH2Cl2/MeOH was added dropwise for 30 min to a stirred solution of trityl compound 44 (0.24 g, 0.18 μmol) in 1.4 mL of 6:1 CH2Cl2/MeOH at 0° C. After 4 h, the reaction mixture was quenched with saturated aqueous NaHCO3 (20 mL) and extracted with Et2O (2×10 mL). The organic phase were separated, dried with MgSO4, filtered and concentrated. The residue was purified by flash chromatography (EtOAc/hexane 1:9) to yield 45 (0.15 g, 77%) as a colorless oil: IR (CHCl3) 3432, 2956, 2856, 1613, 1514, 1471, 1462, 1360, 1250, 1082, 835, 773 cm−1; 1H NMR (300 MHz, CDCl3) δ 7.29 (m, 2H), 6.88 (m, 2H), 6.58 (ddd, J=16.9, 10.6, 10.6 Hz, 1H), 6.00 (t, J=11.0 Hz, 1H), 5.63 (m, 3H), 5.38 (t, J=11.0 Hz, 1H), 5.27 (dd, J=11.2, 8.3 Hz, 1H), 5.17 (d, J=16.8 Hz, 1H), 5.10 (d, J=10.3 Hz, 1H), 4.53 (m, 3H), 4.08 (d, J=4.4 Hz, 2H), 3.90 (m, 1H), 3.81 (s, 3H), 3.62 (m, 1H), 3.33 (m, 2H), 2.99 (ddd, J=10.0, 6.8, 3.2 Hz, 1H), 2.57 (m, 1H), 2.39 (m, 1H), 1.63 (m, 3H), 1.42 (m, 3H), 1.28 (m, 5H), 1.11 (d, J=6.8 Hz, 3H), 0.97 (d, J=6.8 Hz, 3H), 0.96 (d, J=6.9 Hz, 3H), 0.93 (s, 9H), 0.91 (s, 18H), 0.89 (m, 3H), 0.88 (s, 9H), 0.81 (d, J=6.7 Hz, 3H), 0.80 (d, J=6.2 Hz, 3H), 0.10 (s, 3H), 0.09 (s, 3H), 0.08 (s, 6H), 0.06 (s, 3H), 0.05 (s, 6H), 0.03 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 159.0, 146.9, 135.2, 134.6, 133.0, 132.7, 132.3, 131.4, 129.2, 129.1, 128.9, 127.93, 127.90, 127.2, 84.4, 80.0, 75.0, 72.8, 72.2, 66.6, 63.9, 55.2, 42.4, 41.8, 41.7, 40.5, 35.9, 35.2, 34.6, 32.6, 31.6, 30.5, 26.3, 25.99, 25.96, 25.93, 20.2, 19.2, 18.8, 18.5, 18.2, 18.1, 15.1, 13.2, 9.2, −3.0, −3.3, −3.6, −3.7, −4.2, −4.4, −4.5; LRMS (ESI) 1109.8 [M+Na]+, 823.6, 691.5, 559.4; HRMS (ESI) calcd for C62H118O7Si4Na 1109.7852 [M+Na]+, found 1109.7897; [α]20D+1.6 (c 0.94, CHCl3).
