Ketone halogenation

On α,β-Unsaturated ketones or enones, it's possible to halogenate with iodine selectively on the more saturated alpha on the ketone selectively over the unsaturated side. Iodine is preferred due to it being more reactive than alkyl bromides which makes this reaction quite useful. By using CuO in conjunction with I2, it is possible to achieve this reaction under relatively mild conditions. This reaction undergoes a very reactive enol mechanism, facilitated by the CuO, which allows for the selective addition of I2 on the saturated alpha carbon of the ketone. However, the effectiveness of this reaction depends on the presence of aryl functional groups. == Applications in green chemistry ==

Alpha halogenated products are very useful compounds as they have high reactivity which makes them very prone to reacting. Alpha halogenated ketones react with nucleophiles to create many valuable compounds. However, many of the current method for ketone halogenation use hazardous chemicals, have complex procedures, and/or require a long time to go to completion. Additionally, the polar solvents that are primarily used (DMF, DMSO, and CH3CN) are major environmental pollutants. An experiment conducted by Meshram et al. in 2005 investigated making ketone halogenation a greener reaction, according to the principles of green chemistry. Meshram et al. investigated alternatives to the hazardous chemicals that are primarily used in ketone halogenation, finding that room temperature ionic liquids were a promising option. Room temperature ionic liquids are interesting prospects as they have unique chemical and physical properties, and their properties can be modified by changing the cations that are attached. Additionally, these ionic liquids have high polarity and their ability to solubilize organic and inorganic molecules leads to enhanced reaction rates, which makes them more desirable. Many experiments found that ionic liquids with N-halosuccinimides as the solvent were an effective, greener alternative to conventional solvents. This process also resulted in enhanced yields, reduced reaction time, simplified the procedure, used less harmful chemicals (no strong acids), and did not require catalysts, all of which made the process greener. ==References==