To a solution of ethyl (1R,2R,3S,6S)-6-(aminomethyl)-3-{(1R)-1-[3,5-bis(trifluoromethyl)phenyl]ethoxy}-2-(4-fluorophenyl)cyclohexanecarboxylate (0.07 g, 0.13 mmol, intermediate from Step E) in 30 mL dry toluene was added cyclopentane-1,3-dione (0.064 g, 0.65 mmol) and a catalytic amount (˜0.5 mg) of PTSA. The resulting mixture was heated at reflux for 1 hr. The solvent was removed under vacuum. The residue was dissolved in 10 mL toluene and was cooled to −78° C. under nitrogen. Dibal-H (2 mL, 1.0 M) was added. The reaction mixture was stirred for 16 hr at −78° C., quenched with water and diluted with ethyl acetate (10 mL). The organic layer was separated and the aqueous was extracted with ethyl acetate (10 mL). The combined extracts were washed with brine, dried over MgSO4, filtered and the solvent was removed under vacuum. The residue was purified by preparative TLC (silica gel eluting with 9:1 ethyl acetate: methanol) to give 8 mg of the title compound. MS: (MH)+ 574.2. The rest of the material was still unreacted ester.
