Reaction Steps
To the crude chloro(4-methoxyphenyl)diisopropylsilane (54.8 g, 214 mmol, 1.0 equiv.) was added THF (335 mL) via cannula under positive argon pressure. The solution was chilled to 0° C. and treated with allylmagnesiumchloride (128 mL, 256 mmol, 2.0 M in THF, 1.2 equiv.). After 3 h at 0° C., the solution was allowed to warm to 23° C. with stirring overnight. The mixture was treated with NH4Clsat'd (50 mL) and the aqueous layer extracted with ether (3×500 mL). The combined organic extracts were washed with brine, dried (MgSO4), filtered, concentrated in vacuo. The crude material was purified by silica gel chromatography (3-5% EtOAc/hexanes) to yield 52.86 g (94%) of a slightly cloudy, viscous oil. This reagent distills at 130° C. at 500 mtorr as a colorless oil. TLC Rf=0.40 (9:1 Hexanes/EtOAc). IR (film) 2942, 2865, 1630, 1595, 1504, 1463, 1277 cm−1. 1H NMR (500 MHz, CDCl3) δ7.32 (d, 2H, J=6.84, C3-H,C7-H), 6.18 (d, 2H, J=6.84, C4-H, C6-H), 5.82 (q, 1H, J=8.5, 8.5, C15-H), 4.88 (d, 1H, J=17.05, C16-Hb), 4.76 (d, 1H, J=9.77, C16-Ha), 1.82 (d, 2H, J=7.32, C14-H), 1.17 (q, 2H, J=7.3, C8-H, C11-H), 0.94 (d, 6H, J=7.3, C9-H, C10-H), 0.90 (d, 6H, J=7.3, C12-H, C13-H). 13C NMR (125 MHz, CDCl3) δ160.51, 136.48, 135.70, 125.78, 113.78, 113.62, 55.09, 19.34, 18.22, 18.17, 17.68, 11.30. Anal. Calcd for C16H26OSi: C, 73.22; H, 9.98; Si, 10.70.
