A mixture of tert-butyl [(1S)-2-{[5-fluoro-6-(6-hydroxy-1,3-benzoxazol-2-yl)pyridin-3-yl]oxy}-1-methylethyl]carbamate (770 mg), (3,3-difluorocyclobutyl)methyl methanesulfonate (459 mg), potassium carbonate (317 mg), and DMF (10 mL) was stirred at 60° C. for 2 hr. Then additional (3,3-difluorocyclobutyl)methyl methanesulfonate (459 mg) and potassium carbonate (317 mg) were added, and the mixture was stirred at 60° C. overnight. Water was added, and the mixture was extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate) to give the title compound (780 mg) as a white solid.
