ORGN 117 |
| The effect of methyl substitution on the Diels-Alder radical cation reaction was studied using B3LYP using a 6-31g* basis set. Five separate pathways, one concerted and four stepwise, were examined for each possible position of a methyl substituent. All of the concerted transition structures were destabilized by a second order Jahn-Teller distortion. Stepwise pathways which either had the methyl group on a carbon involved in the initial bond formation or in a position where it could not stabilize the radical/cation were a few kcal/mol above alternate pathways. High transition state energies for the formation of vinylcyclobutane derivatives cause it to be a minor product in general. The pathway which proceeds through an anti intermediate is the most favored while the pathways forming the gauche-out intermediate which converts to the anti intermediate is also strongly represented. Both of the major pathways lead directly to the formation of the methylcyclohexene product. |
|
Process R&D, Physical Organic Chemistry, Heterocycles, Aromatics, Metal-Mediated Reactions
8:00 PM-10:00 PM, Sunday, March 25, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Organic Chemistry |