Chapter 25, Problem 25.4P

Interpretation Introduction

Interpretation:

The homolysis of a $\text{C-H}$ bond can occur at three distinct locations on to $\text{1, 3, 5-trimethylcyclohexane}$, yielding three different free radicals. The structure of each radical is to be drawn, and they are to be ranked in order from the least stable to the most stable.

Concept introduction:

The breaking of a covalent bond, whereby the electrons making up that bond are distributed equally to the atoms which are disconnected, is known as the homolytic bond dissociation or homolysis. In hemolysis, generally radicals are formed. In homolysis, a covalent bond is broken down equally, and each atom acquires a single electron, which is called a radical, and a single barbed arrow () is used to represent the movement of a single electron in a homolysis process. In homolysis, the radicals from breaking of the weakest bond of the molecule give the major products. The weakest bond possesses the smallest bond dissociation energy. The stability order for radicals is ${\text{methyl radical < 1}}^{\text{o}}{\text{radical < 2}}^{\text{o}}{\text{radical < 3}}^{\text{o}}\text{radical}\text{.}$ Since radicals are electron-poor like carbocations, the electron-donating groups increase the stability of the radical.