Substitution and Elimination. Reactions of Alkyl Halides. Substitution, Nucleophilic, Bimolecular – S N 2. Reaction Profile for S N 2 Reaction (Wade). Stereochemistry of S N 2 Reaction Inversion of Configuration. Proof of Inversion of Configuration at a Chiral Center.
Substrate Reactivity Since the energy of the transition state is significant in determining the rate of the reaction, a primary substrate will react more rapidly than secondary (which is much more rapid than tertiary).
Hammond’s Postulate • Related species that are close in energy are close in structure. • In an endothermic reaction, the transition state is similar to the product in structure and stability. • In an exothermic reaction, the transition state is similar to the reactant in structure and stability. • i.e. the structure of the transition state resembles the structure of the most stable species.