To a solution of 2-(4-(cyclopropylmethoxy)-3-fluorophenyl)-1,3-benzoxazol-6-ol (1.00 g), tert-butyl ((2S)-1-hydroxypropan-2-yl)carbamate (0.878 g) and triphenylphosphine (1.32 g) in THF (10 mL) was added dropwise diisopropyl azodicarboxylate toluene solution (1.9 M, 2.64 mL), and the mixture was stirred at room temperature for 16 hr. The reaction mixture was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (NH, hexane/ethyl acetate) to give the title compound (0.744 g). 1H NMR (300 MHz, CDCl3) δ 0.35-0.45 (2H, m), 0.63-0.76 (2H, m), 1.29-1.39 (4H, m), 1.46 (9H, s), 3.91-4.02 (4H, m), 4.04-4.18 (1H, m), 4.70-4.85 (1H, m), 6.95 (1H, dd, J=8.7, 2.3 Hz), 7.04 (1H, t, J=8.3 Hz), 7.10 (1H, d, J=2.3 Hz), 7.60 (1H, d, J=8.7 Hz), 7.84-8.01 (2H, m).
