Reaction Steps
To a solution of 45 (4.60 g, 17.7 mmol) in ethyl ether (150 mL) at 0° C. was added dropwise over 5 min lithium aluminum hydride (1 M in ethyl ether, 88.3 mmol). After stirring for 15 min at 0° C. under argon, the reaction mixture was diluted with ethyl ether (200 mL) and quenched with saturated Na2SO4 solution until evolution of hydrogen had ceased. The mixture was dried with solid Na2SO4 and filtered. The residue was extracted with ether (50 mL) and the organic extracts combined. Concentration provided a yellow oil of 46 as a mixture of diastereomers (3.6 g, 78%). This product was used in the next reaction without further purification: Rf=0.50 (1/9 EtOAc:hexane); 1H NMR (300 MHz, CDCl3) δ 7.58-7.53 (m, 2H), 7.39-7.34 (m, 3H), 5.95-5.82 (m, 1H), 5.03-4.89 (m, 2H), 3.70 (dd, J=12.0, 2.3 Hz, 1H), 2.15-2.07 (m, 2H), 1.86-1.76 (m, IH), 1.59-1.49 (m, 2H), 1.23-1.12 (m, 1H), 1.03-0.84 (m, 7H), 0.33 and 0.34 (two singlets due to diastereomers, 3H); 13C NMR (75 MHz, CDCl3) δ 141.5, 135.8, 135.6, 134.7, 134.6, 129.6, 129.5, 128.2, 128.1, 113.2, 62.5, 62.1, 42.3, 42.2, 27.5, 24.2, 24.1, 23.6, 20.7, 20.8, 10.7, 10.5, −7.9, −8.0; IR (neat) 3571 (w), 3434 (m, br), 3069 (m), 2954 (s), 2913 (s), 2872 (m), 1638 (m), 1466 (m), 1427 (m), 1366 (w), 1251 (m), 1111 (s), 993 (m), 902 (m), 790 (s), 736 (s), 700 cm−1; MS (CI/CH4) m/e (rel. intensity) 263 (M++1, 2), 247 (13), 235 (10), 233 (12), 231 (13), 207 (13), 187 (11), 177 (20), 176 (15), 175 (69), (69), 151 (23), 137 (100), 131 (12), 115 (41). Anal. Calcd for C16H26OSi: C, 73.22; H, 9.98. Found: C, 72.85; H, 10.24.
