n-Butyllithium (1.6 M solution in hexane; 7.1 ml; 11.4 mmol) was added dropwise at 0° C. to a solution of aniline (0.53 g; 5.7 mmol) in 10 ml THF. The mixture was allowed to come to RT and was subsequently stirred for 1 h. A solution of (4-dimethylamino-4-phenyl-cyclohexyl)-acetic acid ethyl ester (1.5 g; 5.2 mmol) in 15 ml THF was added dropwise at −78° C. The mixture was subsequently stirred for 1 h and then allowed to come to RT. It was hydrolysed with ammonium chloride solution and extracted with MC. After concentration, the crude product was chromatographed on silica gel (eluent:ether). 308 mg (18%) of the less polar and 620 mg (36%) of the more polar diastereoisomer were obtained.
