Water → 4-Oxo-1-iodo-trans-1-octene

To a solution of 6.4 g. of 4-hydroxy-1-iodo-trans-1-octene (U.S. Pat. No. 4,061,671, Ex. 4) in 25 ml. of ether, cooled in an ice-bath under argon, is added dropwise over 15 minutes, 25 ml. of a solution prepared by dissolving 100 g. of sodium dichromate dihydrate in 300 ml. of water, followed by 136 g. of sulfuric acid with ice-bath cooling and subsequent dilution to 500 ml. After addition, the mixture is stirred at room temperature for 2 hours and diluted with ether. The ether phase is separated and saved. The aqueous phase is extracted with ether. The ether solutions are combined, washed with saturated sodium chloride solution, 5% sodium thiosulfate solution, twice with saturated sodium chloride solution, dried over magnesium sulfate and taken to dryness, giving the product as an orange oil.