To a stirred solution of methyl 2-hydroxypyridine-5-carboxylate (1.00 g, 6.529 mmol), N-tert-butoxycarbonylprolinol (1.31 g, 6.529 mmol), and Ph3P (2.06 g, 7.836 mmol) in THF (10 mL) was added DIAD (1.54 mL, 7.836 mmol) at room temp, and the resulting mixture was stirred for 13 hr at 70° C. The mixture was concentrated and the residue was chromatographed on silica-gel with n-hexane:EtOAc (3:1, v/v) as eluent to give 712.3 mg (32%) methyl 2-[[1-(tert-butoxycarbonyl)-2-pyrrolidinyl]methoxy]pyridine-5-carboxylate as a pale yellow 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), 4.48 (br s, 1H), 6.75 (m, 1H), 8.15 (m, 1H), 8.79 (m, 1H); MS (FAB) m/z 337 (M++1).
