Reaction Steps
TBSCl (0.92 g, 6.11 mmol) was added to a solution of above alcohol 61 (2.51 g, 6.11 mmol) and imidazole (0.46 g, 6.76 mmol) in CH2Cl2 (20 mL). The resulting slurry was stirred for 1 h at room temperature. The organic phase was washed with water (100 mL) and brine (2×100 mL). After drying over MgSO4, filtration and evaporation under vacuum, the residue was used directly in next step: IR (CHCl3) 2930, 2856, 1613, 1513, 1471, 1360, 1250, 1098, 1040, 835, 773 cm−1; 1H NMR (300 MHz, CDCl3) δ 7.29-7.26 (m, 2H), 6.90-6.88 (m, 2H), 4.46 (d, J=11.6 Hz, 1H), 4.42 (d, J=11.6 Hz, 1H), 3.81 (s, 3H), 3.62 (t, J=6.3 Hz, 2H), 3.58-3.52 (m, 2H), 3.28 (dd, J=8.8, 7.7 Hz, 1H), 2.02-1.94 (m, 1H), 1.66-1.54 (m, 2H), 1.52-1.39 (m, 2H), 1.28-1.18 (m, 1H), 0.99 (d, J=6.9 Hz, 3H), 0.94 (s, 9H), 0.92 (s, 9H), 0.89 (d, J=6.8 Hz, 3H), 0.09 (s, 6H), 0.07 (s, 3H), 0.06 (3H); 13C NMR (75 MHz, CDCl3) δ 159.0, 130.9, 129.0, 113.6, 77.5, 72.8, 72.6, 63.4, 55.1, 38.0, 36.3, 31.1, 30.8, 26.1, 25.9, 18.4, 18.3, 15.2, 14.4, −3.8, −4.1, −5.3; LRMS (ESI) 547.4 [M+Na]+413.3, 212.1; HRMS (ESI) calcd for C29H56O4Si2Na 547.3615 [M+Na]+, found 547.3638; [α]20D−9.9 (c 2.5, CHCl3).
