Chapter 7, Problem 68PP

Interpretation Introduction

Interpretation:

The $\text{1-Bromobicyclo}\left[\text{2,2,2}\right]\text{octane}$ is not reactive in E2 reaction when treated with a strong base is needed to be explained.

Concept Introduction:

Elimination Reaction: It is just reverse reaction of addition where substituent from the given molecule is removed via $E1$ (the reaction depends only on the substrate involved in the reaction) or $E2$ (the reaction depends on both of the substituents in the reaction) mechanism.

$E2$Elimination reaction: $E2$ elimination occurs in a compound when the leaving group is antiperiplaner to the proton in presence of strong base. If the base is bulky in nature, least substituted alkene is favorable and the base is not bulky and stronger in nature, most substituted alkene is the favorable product.

For E2 elimination reaction, proton should be present at $\text{β}$ position to the leaving group in antiperiplaner way.

Zaitsev’s Rule: It is elimination reaction in which the formation of olefin on most hindered or highly substituted position

According to Bredt’s rule, a bridgehead carbon of a small bicyclic system (upto six membered) cannot possess a $\text{C}\text{=}\text{C}$ double bond.