A solution of 2-(3-(3-methoxyphenyl)-3-(2-methylphenyl)-2-propen-1-yloxy)ethanol (7.6 g, 25.4 mmol) in dry toluene (150 ml) was cooled on an ice-bath and a solution of n-butyllithium in hexanes (11.2 ml, 2.5 M) was added dropwise. The reaction mixture was stirred for 0.5 h at room temperature and p-toluenesulphonyl chloride (5.3 g, 28 mmol) was added. The mixture was stirred at room temperature for 1.5 h. Ethyl (R)-3-piperidinecarboxylate (8.8 g, 50 mmol) and potassium carbonate (7.7 g, 50 mmol) were added and the mixture was stirred at room temperature for 4 h. Toluene (100 ml), acetone (50 ml) and potassium iodide (1.7 g) were added and the reaction mixture was heated at 75° C. for 84 h. The cooled reaction mixture was filtered and the solvent evaporated in vacuo. The residue was submitted to flash chromatography on silica gel (250 g) using a mixture of n-heptane and ethyl acetate (4:1) as eluent to give 7.5 g (68%) of (R)-N-(2-(3-(3-methoxyphenyl)-3-(2-methylphenyl)-2-propen-1-yloxy)ethyl)-3-piperidinecarboxylic acid ethyl ester as an oil. TLC: rf=0.20 (SiO2 ; ethyl acetate).
