Question

Plz explain the saytzeff's rule.

Answer 1

Zaitsev's rule (or Saytzeff's rule, Saytzev's rule) is an empirical rule for predicting the favored alkene product(s) in elimination reactions. While at the University of Kazan, Russian chemist Alexander Zaitsev studied a variety of different elimination reactions and observed a general trend in the resulting alkenes. Based on this trend, Zaitsev stated, "The alkene formed in greatest amount is the one that corresponds to removal of the hydrogen from the β-carbon having the fewest hydrogen substituents." For example, when 2-iodobutane is treated with alcoholic potassium hydroxide (KOH), 2-butene is the major product and 1-butene is the minor product.[1]

A general example of Zaitsev's rule.

More generally, Zaitsev's rule predicts that in an elimination reaction, the most substituted product will be the most stable, and therefore the most favored. The rule makes no generalizations about the stereochemistry of the newly formed alkene, but only the regiochemistry of the elimination reaction. While effective at predicting the favored product for many elimination reactions, Zaitsev's rule is subject to many exceptions

Answer 2

Saytzeff's rule :

During intramolecular dehydration, if there is a possibility to form a carbon - carbon double bond at different locations, the preferred location is the one that gives the more (highly) substituted alkene i.e., the stable alkene.