4-Dimethylaminopyridine (catalytic amount), triethylamine (68 μl) and propionyl chloride (42 μl) were added to a stirred solution of [4-(2,4-bis{[tert-butyl(dimethyl)silyl]oxy}phenyl)cyclohexyl]methanol in anhydrous dichloromethane (3 ml) at room temperature under argon. After 16 hr, the reaction mixture was partitioned between water (10 ml) and ethyl acetate (20 ml). The layers were separated and the aqueous layer was extracted with ethyl acetate (2×20 ml). The combined organic extracts were dried over magnesium sulfate and evaporated in vacuo. The residue was purified by flash column chromatography (SiO2, ethyl acetate/petrol, 1:19 v/v) to give the title compound as a yellow oil and a mixture of diastereoisomers (114 mg, 92%); δH (CDCl3) −0.04 (6H, s), 0.02 (6H, s), 0.96 (9H, s), 1.00 (9H, s), 1.08-1.18 (3H, m), 1.20-2.10 (9H, m), 2.24-2.40 (2H, m), 2.76-2.92 (1H, m), 3.94 (0.6H, d), 4.18 (0.4H, d), 6.26 (1H, m), 6.40 (1H, dd), 6.94-6.98 (1H, m).
