tert-Butyl[3-{[tert-butyl(dimethyl)silyl]oxy}-4-(4-methylenecyclohexyl)phenoxy]dimethyl silane (135 mg) was dissolved in anhydrous THF (5 ml) with stirring and cooled to −78° C. 9-Borabicyclo[3.3.1]nonane (3.13 ml, 0.5M in THF) was added to the stirred solution and the resulting reaction mixture allowed to warm to room temperature over 3 hr and then stirred for 3 days. Cooling to 0° C. was followed by addition of hydrogen peroxide (1 ml, 30% aqueous solution) and sodium hydroxide (1 ml, 2M aqueous solution). The reaction mixture was allowed to warm to room temperature with stirring over 1 hr, cooled to 0° C., and saturated aqueous sodium metabisulphate solution (30 ml) was added. The layers were separated and the aqueous layer extracted with ethyl acetate (3×20 ml). The combined organic phases were washed with brine (20 ml), dried over anhydrous magnesium sulphate, and concentrated in vacuo. Purification via flash column chromatography (SiO2 eluting with petroleum ether:diethyl ether, 3:17 v/v) afforded the desired product as a yellow oil (73 mg, 52%). δH (CDCl3): 0.18 (6H, s), 0.22 (6H, s), 0.97 (9H, s), 1.00 (9H, s), 1.03-1.15 (0.5H, m), 1.22-1.33 (0.5H, m), 1.43-1.61 (4H, m), 1.77-1.94 (4H, m), 2.75-2.92 (1H, m), 3.47 (1H, d), 3.70 (1H, d), 6.26-6.29 (1H, m), 6.37-6.40 (1H, m), 6.93-6.97 (1H, m).
