Purification of Cyclohexene for Cyclopropanation Reactions

Environmentally friendly reactions yielding cis-cyclopropanes are desired in the insecticide industry as these are most effective at reducing the population of insects while remaining benign to the environment. We are exploring the best parameters for the most effective cis-cyclopropanation reactions. An alkene and a diazo compound react together in the presence of a dirhodium catalyst to produce cyclopropanes. First however, the starting materials must be pure. Alfa Aesar supplies cyclohexene which is reported to be 99% pure, however, Gas column chromatography/Mass spectroscopy reveals that the sample is only 3% cyclohexene. Using an adopted published procedure, we discovered that distillation under nitrogen produces cyclohexene in greater than 95% pure. This is suitable for use in cyclopropanation reactions

Purification of Ethyl Diazoacetate by Vacuum Distillation for use in Cyclopropanation Reactions

Environmentally friendly insecticides have long been desired in the production of food. Pyrethiod compounds not only decompose under light and heat, but they are highly toxic to insects while having effectively no toxicity to mammals. The cis-cyclopropane ring in pyrethiod insecticides is the most challenging component to synthesize. We are exploring the best parameters for the most effective cis-Cyclopropanation reactions. An alkene and a diazo compound react together in the presence of a dirhodium catalyst to produce cyclopropanes. First however, the starting materials must be pure. My part of the project is to purify ethyl diazoacetate(EDA). Column chromatography has been used, but yielded no fraction containing EDA as determined by Gas chromatography/Mass spectrometry. Extraction of EDA with sodium carbonate solution yielded similar results. Thus, I turned to distillation at reduced pressure. This method produced EDA in high enough purity to be used in cyclopropanation reactions. The purity of EDA was determined by H-1 nuclear magnetic resonance spectroscopy