To a stirred solution of methyl 2-hydroxypyridine-5-carboxylate (269.8 mg, 1.762 mmol), N-tert-butoxycarbonylprolinol (354.6 mg, 1.762 mmol), and Ph3P (554.6 mg, 2.114 mmol) in THF (10 mL) was slowly added DIAD (0.42 mL, 2.114 mmol) at room temp, and the resulting mixture was stirred for 6 hr at 70° C. The reaction mixture was concentrated and the residue was chromatographed on silica-gel with n-hexane:EtOAc (5:1, v/v) as eluent to give 262.5 mg (44%) methyl 2-[[1-(tert-butoxycarbonyl)-2-pyrrolidinyl]methoxy]pyridine-5-carboxylate as an oil. 1H-NMR (400 MHz, CDCl3) δ 1.47 (s, 9H), 1.85–1.98 (m, 4H), 3.37 (br s, 2H), 3.92 (s, 3H), 4.12–4.33 (br m, 2H),4.4 (br s, 1H),6.75(m, 1H),8.15 (m, 1H), 8.79 (m, 1H); MS (FAB) m/z 337 (M++1).
