Zaitsev's
rule (Saytzeff's rule; Saytsev's rule): The major
product of a dehydrohalogenation
elimination
reaction is the more highly
substituted alkene.
The rule does not apply to eliminations
other than dehydrohalogenation.
 |
Base |
 |
+ |
 |
|
| Trisubstituted alkene | Disubstituted alkene | ||||
| Base
= -OCH2CH3 |
79% |
21% |
This E2 elimination reaction obeys Zaitsev's rule. | ||
| Base
= -OC(CH3)3 |
27% |
73% |
This Hofmann elimination reaction does not obey Zaitsev's rule. |