Ligand assisted transition metal catalysis used in the oxidation of alkenes is an area of research that is always growing. Yet, there is a void in the understanding of how to control the chemoselectivity of reaction. To determine the extent to which the electron density around the transition metal influences selectivity, a series of cobalt salen catalysts, with various electronic densities at the active site, were tested in the oxidation of cyclohexene with t-BuOOH. The changes to the electron density were determined by the Hammett σ-values associated with the substituents at the 5,5'-position on the salen ligand which increases or decreases the partial positive characteristic of the transition metal. When changed from hydrogen to electron withdrawing or donating substituents a reduction in enone chemoselectivity was seen. This also slowed the activity of the catalysts and decreased overall yield.
|Advisor:||Buonora, Paul T.|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 50/04M, Masters Abstracts International|
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