1. CH 6-7 Elimination Reactions – Part I
All SN1 reactions, and some SN2 reactions are accompanied by Elimination Reactions to form alkene products:
The Nuc acts as a base, grabbing an acidic b-H.
The stronger the base, the more elimination product. +

2. Keys to Interpreting Elimination Reactions
In the substrate, where is the a-carbon (contains Lg), and the b-C’s & b-H’s? Double bond forms between a-C & b-C);
Evaluate substrate structure: 1o, 2o, or 3o alkyl halide
Is the nucleophile a weak or strong base; small or bulky?
Mechanism(s)? (SN1&E1, SN2&E2, only SN2, only E2)
Products? For Elimination Reactions: How many alkene products are formed and what is the structure and geometry of the alkene products (cis vs trans)?

3. The E2 Elimination Mechanism
E2: “Elimination….Bimolecular”
Rate = k [nucleophile] [substrate] (2nd order reaction)
Nucleophile is a strong base
“Concerted” Mechanism:
E2 may accompany an SN2 reaction (not always).

4. The E2 Elimination Mechanism – T.S.