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 added to a solution of TBS ether 12 (4.46 g, 7.07 mmol) in THF (10 mL). The mixture was stirred overnight at room temperature and quenched with sat'd NaHCO3 (100 mL). The aqueous layer was separated and extracted with Et2O (3×50 mL). The combined organic layers were washed with sat'd CUSO4 (3×50 mL), dried over MgSO4, and concentrated. Flash column chromatography (EtOAc/hexane 1:4) afforded 3.26 g (89%) of alcohol 13 as a colorless oil: IR (CHCl3) 3407, 2955, 2928, 2856, 1490, 1471, 1448, 1254, 1058, 1031, 836, 773, 705 cm−1; 1H NMR (300 MHz, CDCl3) ε7.57 (m, 6H), 7.37 (m, 9H), 5.78 (dd, J=15.6, 6.5 Hz, 1H), 5.73 (dt, J=15.5, 4.8 Hz, 1H), 3.91 (m, 1H), 3.82 (d, J=5.9 Hz, 2H), 3.69 (d, J=4.4 Hz, 2H), 2.51 (m, 1H), 2.22 (br, 1H), 1.77 (m, 2H), 1.13 (d, J=6.8 Hz, 3H), 1.03 (s, 9H), 0.21 (s, 3H), 0.19 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 144.2, 134.1, 128.6, 127.7, 127.1, 126.9, 86.8, 74.3, 64.9, 60.4, 42.0, 34.8, 25.9, 18.0, 14.5, −4.4, −4.6; LRMS (ESI) 539.2 [M+Na]+, 243.2; HRMS (ESI) calcd for C33H44O3Si1Na 539.2957 [M+Na]+, found 539.2976; [α]20D−2.8 (c 2.0, CHCl3).
