Ethyl cyclohexylideneacetate was prepared as follows: to a clean, dry 250 mL R.B. was added cyclohexanone (5 g, 5.100 mmol) and two carbons Wittig reagent (19.537 g, 56.1 mmol). Then, the temperature was raised to 120C. The reaction mixture was refluxed for 24 hours. After completion of the reaction, toluene was removed under vacuum. After removal of toluene, it was filtered through a 3 cm thick bed of diatomaceous earth in 5% ethyl acetate/petroleum ether system to remove triphenylphosphine oxide. The filtrate was concentrated under reduced pressure and the residue was purified on silica gel column chromatography using ethyl acetate/petroleum ether (2:98) to afford the unsaturated ester ethyl cyclohexylideneacetate (24.7 g, 98%) as a clear liquid. Rf (5% EtOAc/hexane): 0.5. yield: 98%.
