Question

What is Saytzeff’s rule? Explain with an example.

What is Saytzeff’s rule?

Answer 1

When a haloalkane may be dehydrohalogenated in two different ways to produce two distinct alkenes, the most substituted alkene is the one with the greatest amount of alkyl groups connected to the doubly bound carbon atoms.

For example, when 2-chlorobutane is heated with alcoholic KOH, 80% of but-2-ene and 20% of but-1-ene are produced. Because but-2-ene has two methyl groups affixed to the doubly bonded carbon atoms, it is more substituted than but-1-ene, which has only one methyl group attached to the doubly bonded carbon atoms.