Chapter 8, Problem 42P

(a)

Interpretation Introduction

Interpretation:

Preparation of 2-methoxybutane using alkyl halide as a starting material has to be explained.

Concept Introduction:

${\text{S}}_{\text{N}}2$Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on both of the molecules involved. The bond making and the bond breaking process happens simultaneously in this reaction.

Structure of the substrate plays major role in the reactivity of ${\text{S}}_{\text{N}}2$ reaction. If the substrate is more substituted then the rate of the reaction will becomes slower. Since the mechanism of ${\text{S}}_{\text{N}}2$ reaction proceeds through backside attack on the substrate, it depends on steric factor that if more groups attached near the leaving group the reactivity becomes slower.

Leaving group: It is a fragment that leaves the chemical compound with pair of electrons in a heterolytic bond cleavage. The ${\text{S}}_{\text{N}}2$ reactivity increases in molecule with better leaving group.

Down the group, atom size decreases which in turn reduces the tendency of atom for donating electrons and hence basicity decreases making them a better leaving group.

Nucleophile donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.

An alkyl halide favors ${\text{S}}_{\text{N}}2$ reaction by high concentration of the good (negatively charged) nucleophile in the aprotic polar solvent or by high concentration of the good (neutral) nucleophile in the protic polar solvent

(b)

Interpretation Introduction

Interpretation:

Preparation of 1-methoxybutane using alkyl halide as a starting material has to be explained.

Concept Introduction:

${\text{S}}_{\text{N}}2$Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on both of the molecules involved. The bond making and the bond breaking process happens simultaneously in this reaction.

Structure of the substrate plays major role in the reactivity of ${\text{S}}_{\text{N}}2$ reaction. If the substrate is more substituted then the rate of the reaction will becomes slower. Since the mechanism of ${\text{S}}_{\text{N}}2$ reaction proceeds through backside attack on the substrate, it depends on steric factor that if more groups attached near the leaving group the reactivity becomes slower.

Leaving group: It is a fragment that leaves the chemical compound with pair of electrons in a heterolytic bond cleavage. The ${\text{S}}_{\text{N}}2$ reactivity increases in molecule with better leaving group.

Down the group, atom size decreases which in turn reduces the tendency of atom for donating electrons and hence basicity decreases making them a better leaving group.

Nucleophile donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.

An alkyl halide favors ${\text{S}}_{\text{N}}2$ reaction by high concentration of the good (negatively charged) nucleophile in the aprotic polar solvent or by high concentration of the good (neutral) nucleophile in the protic polar solvent

(c)

Interpretation Introduction

Interpretation:

Preparation of dicyclohexyl ether using alkyl halide as a starting material has to be explained.

Concept Introduction:

${\text{S}}_{\text{N}}2$Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on both of the molecules involved. The bond making and the bond breaking process happens simultaneously in this reaction.

Structure of the substrate plays major role in the reactivity of ${\text{S}}_{\text{N}}2$ reaction. If the substrate is more substituted then the rate of the reaction will becomes slower. Since the mechanism of ${\text{S}}_{\text{N}}2$ reaction proceeds through backside attack on the substrate, it depends on steric factor that if more groups attached near the leaving group the reactivity becomes slower.

Leaving group: It is a fragment that leaves the chemical compound with pair of electrons in a heterolytic bond cleavage. The ${\text{S}}_{\text{N}}2$ reactivity increases in molecule with better leaving group.

Down the group, atom size decreases which in turn reduces the tendency of atom for donating electrons and hence basicity decreases making them a better leaving group.

Nucleophile donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.

An alkyl halide favors ${\text{S}}_{\text{N}}2$ reaction by high concentration of the good (negatively charged) nucleophile in the aprotic polar solvent or by high concentration of the good (neutral) nucleophile in the protic polar solvent