Chapter 25, Problem 25.26P

Interpretation Introduction

Interpretation:

How the given transformation would carry out using at least one radical chain reaction is to be explained.

Concept introduction:

The bromination at the carbon adjacent to benzylic carbon cannot be possible in single step from ethyl benzene. Thus, such transformation can be carried out through more than one reaction steps. The reaction steps for such transformation can be identified by retrosynthetic analysis. Then by reversing the reactions and adding the appropriate reagents, the synthesis can be written. Benzylic bromide can be prepared by radical reaction using $\text{NBS}$. Benzylic bromide, on based catalyzed dehydrogenation, undergoes elimination of $\text{HBr}$, forming a double bond. The bromine at carbon adjacent to benzylic position can be incorporated by anti-Markovnikov addition of $\text{HBr}$ in the presence of peroxide.