To a mixture of didocosahexaenoyl methanol (IV, 1.2 g, 1.9 mmol) and anhydrous potassium carbonate (0.1 g) in 30 mL of CH2Cl2 was added pyridinium chlorochromate (PCC, 1.05 g, 4.8 mmol). The resulting suspension was stirred at room temperature for 2 hours. Ether (120 mL) was then added into the mixture, and the resulting brown suspension was filtered through a pad of silica gel (75 mL). The pad was further washed with ether (3×75 mL). The ether filtrate and washes were combined. Evaporation of the solvent gave 1.3 g of an oily residual as a crude product. The crude product was purified by column chromatography on silica gel (230-400 mesh, 40 mL) eluted with 0-3% ethyl acetate in hexanes. This afforded 0.83 g (69%) of didocosahexaenoyl ketone (V).
