Event Description
Keith Woerpel, PhD, New York University
"Stereoselective Addition Reactions to Carbon Electrophiles:Conformational Analysis, Stereoelectronic Effects, and Reactivity"
Because oxygen-stabilized carbocations (oxocarbenium ions) are important intermediates in both synthetic chemistry and glycobiology, a deeper understanding of their structures and reactivities would benefit both fields. Our research demonstrates that electronic effects exert powerful influences on the conformational preferences of these cations. When the oxocarbenium ion is substituted with alkoxy groups, conformers are generally favored that maximize stabilizing electrostatic attractions between the partially negatively charged substituents and the cationic carbon atom. Nearby electron-donating groups that can engage in neighboring-group participation may or may not be involved in bond-forming reactions depending upon the substrate. Other phenomena observed with oxocarbenium ions can also be applied to understand selectivities (or lack thereof) in reactions of carbonyl compounds. |
