3) Radical reactions INTRODUCTION

page 5

What is a radical?

Atom with a unpaired electron

Radicals are

electrophiles due to unfilled orbitals, highly reactive

What is the e- geometry?

Trigonal planar, sp2 with a half-filled p orbital

Radical stability order (unstable to stable)

primary, secondary, tertiary, allylic

What is the most stable radical?

An allylic radical, has resonance

Why is the trend this way?

More carbons = more places to SHARE the electron density, making the molecule more stable

What happens when you stabilize a radical?

It becomes less reactive.

Why are primary radicals less stable than secondary radicals and so on?

When we talk about R groups (like alkyl groups), we mean groups that contain carbon-hydrogen bonds (such as methyl, ethyl, etc.). These groups are electron-donating, meaning they push electrons towards the radical site. This helps to stabilize the unpaired electron because the electron density around the radical increases, making it less reactive.