Chapter 10.5, Problem 15E

(a)

Interpretation Introduction

Interpretation: Structure of the major product expected from the ionic addition of $\text{HBr}$ to the substrate indicated should be written.

  

Concept introduction: Alkenes are considered electron rich and undergoes addition reaction in presence of electrophilic halo acids. The product formed is governed by Markovnikov’s Rule. Rule suggests that negative part of halo acid HX must go to the carbon that has more alkyl substituents or less $\text{H}$ atoms. In general tertiary carbocation are more reactive than primary carbocation. For example, electrophilic addition mechanistic pathway when $\text{HBr}$ adds to polar $1\text{-hexene}$ is illustrated below.

  

(b)

Interpretation Introduction

Interpretation: Structure of the major product expected from the ionic addition of $\text{HBr}$ to the substrate indicated should be written.

  

Concept introduction:Alkenes are considered electron rich and undergo addition reaction in presence of electrophilic halo acids. The product formed is governed by Markovnikov’s Rule. Rule suggests that negative part of halo acid HX must go to the carbon that has more alkyl substituents or less $\text{H}$ atoms. In general, tertiarycarbocations are more reactive than primary carbocations.

(c)

Interpretation Introduction

Interpretation: Structure of the major product expected from the ionic addition of $\text{HBr}$ to the substrate indicated should be written.

  

Concept introduction:In first step of addition of $\text{HBr}$ , it undergoes cleavage and this generates acidic proton. This proton is added at one of the olefinic carbons to form a carbocation intermediate. In step 2, the secondary carbocation is attacked by bromide ion at electron-deficient site to form Markovnikov’s product.