To a solution of 2.0 g (6.84 mmol) of (1S,2R)-2-(3-chlorophenyl)-1-(4-chlorophenyl)but-3-en-1-amine (Example 115, Step E), dicyclopropyl ketone (7.54 mL, 68.4 mmol), and acetic acid (1.96 mL, 34.2 mmol) in methanol (25.0 mL) was added sodium cyanoborohydride (1.44 mL, 27.4 mmol) at rt. The resulting mixture was stirred at 50° C. for 2 days. Acetic acid (1.5 ml) and sodium cyanoborohydride (0.6 g) were added again and heating was continued overnight. 200 ml of ethyl acetate was added, and the organic layer was washed consecutively with K2CO3 solution and sat. NaCl solution, dried over K2CO3, filtered and the filtrate was concentrated under reduced pressure at 60° C. The mixture was purified by flash chromatography on silica gel (eluent: DCM/MeOH, 95/5) to give the title compound.
