Question

Arrange the following alkenes in the order of increasing stability and rank the following substrates toward E1 reactivity. Explain why as well please.

4. Arrange the following alkenes in the order of increasing stability (5pts, No partial points); Lowest Highest stability 5. Rank the following substrates toward El reactivity (5pts, No partial points); 1 2 3 4 Highest reactivity Lowest

Answer 1

4. By Saytzev rule, more substitited alkene is more stable than less substitited alkene.

Order: tetrasubstitited>trisubstituted>disubstituted>monosubstituted alkene

And bridge head alkene (dobldo bonds at bridge head carbon) are unstable due to restricted rotation

Hence order: 2 <1 < 3 < 4

5. E1 elimination involves the formation of carbocation intermediate

More the stability of Cation, more the reactivity of alkene.

Order: 1< 4 < 2< 3

Vinyl cation is unstable,

Allylic cation is more stable due to resonance.