CHEM10006 Lecture Notes - Lecture 26: Rate-Determining Step, Electrophilic Addition, Elimination Reaction
Document Summary
An elimination reaction is where an atom or group of atoms is lost and a multiple bond is formed. Two mechanisms that can be distinguished by rate measurement. E1: two step reaction proceeding through a carbocation intermediate. E2: a one step reaction involving loss of leaving group at the same time as the loss of a proton. The major product(s) of elimination reactions are the most substituted and less sterically crowded alkene(cid:894)s(cid:895) (cid:894))aitsev"s rule(cid:895) Elimination and substitution reactions are frequently in competition with one another and share significant mechanistic similarities. Loss of a leaving group to form the carbocation. This is the same as the first step in sn1 reactions, which is why sn1 by-products can also form. The base removes a proton to form the alkene. Regioselectivity is the preference of one direction of chemical bond making or breaking over all other possible directions, i. e. there is often more than one product possible in an elimination reaction.