Di-tert-butyl azodicarboxylate (0.024 g, 0.10 mmol) was added portionwise to a stirred solution of 6-(4-fluorobenzoyl)-5,6,7,8-tetrahydro-4H-oxazolo[4,5-d]azepine-2-methanol (0.02 g, 0.069 mmol), phenol (0.01 g, 0.10 mmol) and triphenylphosphine (0.027 g, 0.10 mmol) in DCM (0.5 mL) at 0° C. The mixture was stirred at room temperature for 10 minutes and the solvent was evaporated in vacuo. The crude product was purified by flash column chromatography (silica; AcOEt in DCM 0/100 to 40/60). The desired fractions were collected and concentrated in vacuo. The product was further purified by flash column chromatography (silica; AcOEt in heptane 50/50 to 100/0). The desired fractions were collected and the solvents evaporated in vacuo and purified by reverse phase HPLC performed on a C18 XBridge 30×100 mm, 5 μm column (0.1% solution of ammonium formate/ammonium hydroxide buffer pH 9 in ethyl acetate 80/20 to 0/100) to yield 6-(4-fluorobenzoyl)-5,6,7,8-tetrahydro-2-(phenoxymethyl)-4H-oxazolo[4,5-d]azepine (2.07 mg, 8% yield) as an oil. C21H19FN2O3. (Mixture of rotamers ˜60:40) 1H NMR (400 MHz, CDCl3) δ ppm 2.66 (br. s., 1.2 H), 2.78 (br. s., 0.8 H), 3.00 (br. s., 0.8 H), 3.12 (br. s., 1.2 H), 3.62 (br. s., 2.1 H), 3.93 (br. s., 1.9 H), 5.05 (s, 2 H), 6.97-7.04 (m, 1 H), 7.02 (d, J=7.4 Hz, 2 H), 7.12 (t, J=8.7 Hz, 2 H), 7.31 (dd, J=9.1, 7.1 Hz, 2 H), 7.39 (dd, J=8.8, 5.3 Hz, 2 H).
