Anhydrous tetrahydrofuran (5 mL) is added at room temperature to a mixture of 4-(4-hydroxy-azepan-1-yl)-benzoic acid ethyl ester (364 mg, 1.38 mmol), 18-crown-6 (407 mg, 1.52 mmol) and tert-butyl alcohol, potassium derivative (178 mg, 1.52 mmol). The mixture is stirred for 5 minutes and then 4-bromomethyl-5-cyclopropyl-3-(2,6-dichloro-phenyl)-isoxazole (480 mg, 1.38 mmol) is added. After 1.5 h, the solvent is removed and water is added. The aqueous phase is extracted with ethyl acetate. The organic layers are combined, dried over anhydrous sodium sulfate, filtered, and the solvent is removed under reduced pressure. The residue is purified via flash chromatography (40 g silica) eluting with a gradient of ethyl acetate/hexane (0% to 30%) to provide the title compound as a colorless waxy solid (203 mg, 28%). ES/MS m/z 529.0 (M+1).
