| We have conducted correlation studies on ten alkene addition reactions in this project in order to explore the substituent effects on alkene reactivity in these reactions. In these studies, we have correlated the relative reactivities of alkenes versus their measurable characteristics, such as the ionization potentials (IPs), the highest occupied molecular orbital (HOMO) energy levels, and sometimes, the lowest unoccupied molecular orbital (LUMO) energy levels, in order to determine the relative magnitudes of electronic and steric effects in the rate-determining step of the alkene addition. The results from our correlation studies indicate that the majority of the alkene reactions included in this project are electrophilic additions to alkenes either with significant steric effects, such as in acid-catalyzed hydration and complexation with solid iodine, or without significant steric effects, such as in chlorination, bromination, oxidation with chromyl chloride and with chromic acid, ISCN addition, and ICl addition. Only two reactions, oxidation with palladium chloride and homogeneous hydrogenation in presence of Wilkinson's catalyst, were found to be nucleophilic additions with significant steric effects. These results are helpful in predicting alkene relative reactivities in the alkene reactions based on the substituents on the C=C bonds. The patterns of correlation plots in some studies have also provided supportive evidence that helped us in differentiating between alternatively proposed mechanisms for studied alkene additions. |
