ORGN 630 |
| Cyclohexanones substituted with heteroatoms at the 2-position have been synthesized to investigate the influences that these substituents have on the stereoselectivity of nucleophilic substitution reactions. For systems bearing sulfur and iodine at C-2, it is believed that the pseudoaxial conformation is preferred in the ground state of the cation due to hyperconjugative stabilization of the cationic center. This analysis is supported by experimental results demonstrating that selectivity diminishes as electronegativity increases. Our experiments lend support to the possibility that these reactions are operating under Felkin control, that a nucleophile prefers to attack opposite the most sterically encumbering group and/or to attack anti to the substituent bearing the lowest LUMO.
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Physical Organic Chemistry: Calculations, Mechanisms, Photochemistry, and High-Energy Species
8:00 AM-12:00 PM, Thursday, 30 March 2006 Georgia World Congress Center -- C303, Oral
Division of Organic Chemistry |
