CHEM 8A
Lectures 14 & 15
ELIMINATION REACTIONS: E1 vs. E2
The products of an elimination reaction, whether by E1 or E2, almost always look identical. The
difference is that the E1 mechanism occurs with weak bases and the E2 mechanism occurs in
the presence of strong bases. Also, there are stereochemical concerns in the E2 mechanism.
Use the examples of weak and strong bases to determine the products of each reaction
Strong bases (E2) – Alkoxides, Hydroxide
Weak bases (E1) – Water, Alcohols, Carboxylates
Cl
KOt-Bu
(1)
t-BuOH
Cl
CH
OH
3
(2)
Cl
KOt-Bu
(3)
t-BuOH
Cl
(4)
CH
CO
Na
3
2
CH
CO
H
3
2