To a solution of 2,2-difluoro-2-(1-hydroxy-3,3,5,5-tetramethylcyclohexyl)acetate (87.83 g) and Et3N (122 mL) in THF (2000 mL), ethyl chloroformate (30.8 mL) was added at room temperature and the mixture was stirred for 30 minutes. To the reaction mixture, a THF (500 mL) solution of the compound (89.00 g) obtained in Example 1-(1) was added dropwise at room temperature over an hour and the mixture was stirred at room temperature for 20 hours. The reaction mixture was concentrated and AcOEt (2 L) and a saturated aqueous solution of NH4Cl (2 L) were added; after filtering the insoluble matter, the organic layer was separated and washed with saturated aqueous sodium bicarbonate (2 L), dried (MgSO4), filtered and concentrated to give a crude product (165.0 g). A similar method was applied using 2,2-difluoro-2-(1-hydroxy-3,3,5,5-tetramethylcyclohexyl)acetate (34.64 g) and (S)-5-((3,4-dimethoxyphenoxy)methyl)-3-(pyrrolidin-2-yl)isoxazole (35.10 g) to give a crude product (60.10 g), which was combined with the first crude product and further purified by silica gel chromatography (AcOEt/hexane) and NH-form silica gel chromatography (AcOEt/hexane); the purified product was recrystallized (Et2O/pentane) to give the titled compound (134.30 g, colorless powder.)
