CHED 541 |
| Electrocyclization and cycloaddition of azomethine ylides and azaallyl anions offer potential for regio- and stereocontrolled formation of azacycles. Thus, these reactive intermediates have been investigated computationally. Specifically, we have studied the properties of conjugated azomethine ylide and azaallyl anion systems that are theoretically capable of undergoing disrotatory electrocyclization due to their six pi electrons. As ring closure is dependent on the geometry of the intermediates, a computational study of conformer energies and interconversion energy barriers has been conducted. Initial studies suggest that intermediates substituted at the four position favor the U-geometry required for electrocyclization. Further calculations indicate that added steric hindrance at this position gives increased bias toward the U conformer while simultaneously lowering the activation energy required for electrocyclization. Related studies have examined the structural properties that facilitate spontaneous ring opening of 4-oxazolines to produce stabilized azomethine ylides. These and other findings will be reported. Supported by PRF/41664-GB1. |
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Undergraduate Research Poster Session: Organic Chemistry
11:00 AM-1:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |