Chapter 25, Problem 25.34P

Interpretation Introduction

Interpretation:

The major homolysis product when a given compound irradiated with UV light is to be drawn.

Concept introduction:

Homolysis generally breaks the weakest bond in the compound.

The carbon atom attached to more number of alkyl group form weaker bond $\text{(i}\text{.e}{\text{. 1}}^{\text{o}}{\text{ >2}}^{\text{o}}{\text{ > 3}}^{\text{o}}\text{)}$ because the resulting ${\text{C}}^{\text{•}}$ is stabilized by addition electron-donating alkyl group. Also bonds involving allylic or benzylic C atoms tend to be weaker because of the resonance stabilization in the resulting alkyl radical. When C is the part of a $\text{C=C}$ bond (i.e, vinylic or aromatic) owing to additional s characters tends to form a strong bond. Also when C is bond with Br $\text{(C-Br)}$ is weaker than $\text{C-H}$ or $\text{C-C}$ bonds.