Reaction Steps
To a dried round bottom flask, 7 (270 mg, 0.98 mmol), imidazole (134 mg, 1.96 mmol), dimethylaminopyridine (6 mg, 0.05 mmol) were dissolved in dichloromethane (4 mL). Tert-butyldimethylsilyl chloride (222 mg, 1.47 mmol) was then added portionwise and allowed to react for 24 hours. The reaction was then quenched with water, extracted with dichloromethane, dried over Na2SO4 and concentrated in vacuo. Flash chromatography (10% ethyl acetate in hexanes) gave a colourless oil 8 (343 mg, 90%). Rf=0.48 on silica gel (10% ethyl acetate:hexanes. IR(KBr, cm−1) 2983 (w), 1731 (s), 1453 (w), 1370(m), 1150(s), 1031 (m); 1H NMR (400 MHz, CDCl3) δ 7.41-7.39 (1H, m), 7.24-7.22 (2H, m), 7.07-7.05 (1H, m), 6.47 (1H, dd, J=9.9, 1.8 Hz), 5.83 (1H, dd, J=9.7, 2.7 Hz), 5.60 (1H, ddd, J=9.3, 2.9, 2.0 Hz), 5.00 (1H, dd, J=9.3, 0.5 Hz), 4.22-4.15 (2H, m), 3.40 (2H, dd, J=19.6, 16.0 Hz), 1.57 (1H, s), 1.25 (3H, t, J=7.1 Hz), 0.92 (9H, s), 0.13 (3H, s), 0.09 (3H, s); 13C NMR (400 MHz, CDCl3) δ 166.3, 166.2, 136.2, 132.1, 129.4, 128.0, 127.9, 126.5, 125.9, 125.7, 76.4, 71.6, 61.6, 41.7, 25.8, 18.1, 14.0, −4.3, −4.5. HRMS calcd for C17H21O5Si (M+-C4H9): 333.1158. Found: 333.1149.
