Chapter 16.SE, Problem 36MP

Interpretation Introduction

Interpretation:

Given that addition of HBr to 1-phenylpropene yields only (1-bromopropyl) benzene. A mechanism for this reaction is to be proposed and why none of the other regioisomer is produced is to be explained.

Concept introduction:

The addition of HBr to alkenes takes place in two steps. In the first step the π electrons of the double bond picks up the positively polarized hydrogen of HBr to yield a more stable carbocation eliminating a bromide ion. In the next step the bromide ion attacks the carbocation from the less hindered side to yield the product.

To propose:

A mechanism for the reaction in which HBr adds to 1-phenylpropene to yield only (1-bromopropyl) benzene.

To explain:

Why none of the other regioisomer is produced.