Reaction Steps
A solution of 1-oxo-1-[5-(2-pyridyl)oxazol-2-yl]-7-(trimethylsilyl)hept-6-yne (3a, 570 mg, 1.75 mmol, 1 equiv) in anhydrous THF (6 mL) at 0° C. was treated with a solution of Bu4NF in THF (1 M, 2.1 mL, 2.1 mmol). After stirring for 35 min at 0° C., the reaction mixture was quenched with H2O and extracted with EtOAc. The organic layer was dried over anhydrous Na2SO4, filtered and evaporated. Column chromatography (SiO2, 2.5×3 cm, 30% EtOAc-hexanes) afforded 1-oxo-1-[5-(2-pyridyl)oxazol-2-yl]-hept-6-yne (3b, 340 mg, 1.36 mmol, 77%) as a tan solid: 1H NMR (CDCl3, 500 MHz) δ 8.68-8.66 (m, 1H), 7.89-7.86 (m, 2H), 7.82 (td, 1H, J=7.6, 1.8 Hz), 7.34-7.31 (m, 1H), 3.15 (t, 2H, J=7.3 Hz), 2.27 (td, 2H, J=7.2, 2.7 Hz), 1.96 (t, 2H, J=2.7 Hz), 1.94-1.88 (m, 2H), 1.68-1.62 (m, 2H); 13C NMR (CDCl3, 125 MHz) δ 187.9, 157.2, 153.2, 150.1, 146.2, 137.1, 126.8, 124.1, 120.3, 83.8, 68.7, 38.4, 27.7, 22.9, 18.2; IR (film) νmax 2938, 2867, 2115, 1698, 1603, 1575, 1505, 1470, 1426, 1385, 1283, 1245, 1127, 1086, 1024, 991, 962, 853, 785, 743 cm−1; ESI-TOF m/z 255.1135 (C15H14N2O2+H+ requires 255.1128).
