2-Chloro-5-(2-propenyl)-N-(tricyclo[3.3.1.13,7]dec-1-ylmethyl)-benzamide (Example 5a) (9.4 g), pyrazole (0.45 g) and methyltrioxorhenium(VII) (0.40 g) were stirred together in dichloromethane (40 mL) under nitrogen, and hydrogen peroxide (27.5% wt. solution in water, 13 mL) was added dropwise. The reaction was then monitored by HPLC/MS and further portions of pyrazole, methyltrioxorhenium(VII) and hydrogen peroxide were added over a period of 2 days until the reaction mixture consisted of a 1:1 mixture of starting material and product. The mixture was then poured into water (500 mL), extracted into dichloromethane (3×300 mL), washed with 2M aqueous hydrochloric acid (300 mL), brine (300 mL), saturated aqueous sodium thiosulfate (300 mL), dried over anhydrous magnesium sulfate, filtered and concentrated to give an oil. This was purified by column chromatography eluting with 2:1 isohexane/ethyl acetate to give the sub-titled compound (4.71 g).
