Reaction Steps
HF-pyridine in pyridine (40 mL, prepared by slow addition of 12 mL pyridine to 3 mL HF-pyridine complex followed by dilution with 25 mL THF) was slowly added to a solution of TBS ether 35 (4.27 g, 4.10 mmol) in THF (5 mL) at 0° C. The mixture was stirred for 21 h at 0° C. and quenched with saturated aqueous NaHCO3 (100 mL). The aqueous layer was separated and extracted with Et2O (3×50 mL). The combined organic layers were washed with saturated aqueous CuSO4 (3×50 mL), dried over MgSO4, filtered and concentrated. Flash column chromatography (EtOAc/hexane 1:4) afforded 2.55 g (67%) of the alcohol 36 as a colorless oil: IR (CHCl3) 3350, 2956, 2928, 2856, 1471, 1448, 1254, 1086, 836, 773, 705 cm−1; 1H NMR (300 MHz, CDCl3) δ 7.52 (m, 6H), 7.32 (m, 9H), 5.68 (m, 2H), 5.50 (t, J=10.6 Hz, 1H), 5.35 (dd, J=10.9, 8.5 Hz, 1H), 4.61 (t, J=8.5 Hz, 1H), 4.00 (t, J=8.1 Hz, 1H), 3.62 (d, J=3.2 Hz, 2H), 3.58 (dd, J=10.6, 4.3 Hz, 1H), 3.45 (m, 1H), 3.36 (dd, J=9.9, 7.3 Hz, 1H), 2.66 (m, 1H), 2.48 (m, 1H), 1.70 (m, 3H), 1.49 (m, 3H), 1.04 (d, J=6.6 Hz, 6H), 0.97 (s, 18H), 0.93 (m, 6H), 0.87 (s, 9H), 0.18 (s, 3H), 0.16 (s, 3H), 0.11 (s, 6H), 0.10 (s, 3H), 0.08 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 144.3, 134.4, 133.0, 132.1, 128.7, 127.7, 126.8, 86.7, 79.8, 72.3, 67.7, 66.5, 65.1, 42.4, 41.5, 37.3, 35.7, 35.5, 33.3, 26.2, 26.0, 25.9, 19.6, 18.4, 18.14, 18.06, 17.98, 15.7, 13.2, −2.9, −3.6, −3.7, −4.1, −4.2, −4.3; LRMS (ESI) 951.8 [M+Na]+, 771.6, 328.3; HRMS (ESI) calcd for C56H92O5Si3Na 951.6150 [M+Na]+, found 951.6162; [α]20D−12.0 (c 0.71, CHCl3).
