by column chromatography on silica gel using hexanes-ethyl acetate to give 89 mg (59%) of the title product as a syrup; IR (CHCl3) 1630, 1670, 1690 cm−1; 1H NMR (CDCl3) δ 2.0–2.4 (m, 4 H), 4.06 (t, J = 6 Hz, 2 H), 6.08 (d, J = 10 Hz, 2 H), 6.76 (d, J = 10 Hz, 2 H). References Organic oxidation reactions