Chapter FRP, Problem 17P

Interpretation Introduction

Interpretation:

A resonance explanation for the ability of halides of the type ${\text{ROCH}}_2\text{X}$ to undergo ${\text{S}}_{\text{N}}1$ reactions is to be proposed.

Concept introduction:

The rules for drawing resonance structures are as follows:

Only nonbonding electron pairs and pi electrons can participate in conjugation in the formation of various resonating structures.

The single bonds present in the molecule do not break or form in the resonance structures.

The placement of atoms present in the molecule remains fixed.

The octet of all atoms is completely filled.

The resonance effect is the withdrawal or release of electrons through delocalization of $\pi$ electrons. Compounds that contain double bonds in their structures are made up by the overlap of p-orbitals on two adjacent carbon atoms.

Inductive effect is the electronic effect that arises due to electronegativity difference between the atoms at either end of the bonds.

Primary alkyl halide undergoes ${\text{S}}_{\text{N}}2$ mechanism because primary carbocations are not stable and the substrates have less steric hindrance to nucleophilic attack.

Electron withdrawing groups attract electron density toward itself and draw electrons away from the reaction centre.

Electron donating group donate electron density or releases electrons into the reaction centre.

Alkyl group is an electron donating group.