Chapter 18.7, Problem 25ATS

Interpretation Introduction

Interpretation: Resonance structure of anisole should be drawn and regiochemical outcome of a Birch reduction of anisole should be predicted

Concept introduction:

• Resonance is a way of describing delocalized electrons with certain molecules. In which continues delocalization of $\text{π}$ electrons are occurred
• Inductive effect is the electronic effect due to an electronegativity difference between the atoms at the end of the bond.
• Resonance is generally the dominant factor over inductive effect.
• In anisole methoxy group is electron withdrawing because of induction, but it is electron donating because of resonance.
• Birch reduction converts aromatic compound having benzoid ring in to a product 1, 4-cyclohexa diene. The product having hydrogen atoms attached on opposite end of the molecule
• Birch reduction is the reduction of aromatic rings with sodium , potassium or lithium and an alcohol in liquid ammonia. Birch reduction is unlike catalytic hydrogenation
• When benzene with an electron donating group such as alkyl group is treated with Birch reduction, the carbon atom connected to the alkyl group is not reduced. Electron   donating effect destabilizes the radical anion.
• When an electron withdrawing groups are used, different regiochemical outcome is observed. Electron withdrawing   effect stabilizes the intermediate.