Chapter 9, Problem 9.43P

Interpretation Introduction

(a)

Interpretation:

The structure for the given precursor is to be drawn, paying attention to the stereochemistry.

Concept introduction:

${\text{S}}_{\text{N}}\text{2}$ reaction rates are highly sensitive to nucleophilicity, whereas ${\text{S}}_{\text{N}}\text{1}$ reactions are not. Thus, strong nucleophiles favor ${\text{S}}_{\text{N}}\text{2}$ reactions, and weak nucleophiles favor ${\text{S}}_{\text{N}}\text{1}$ reactions. Stereochemical configuration of the product is inert as compared to the reactant; product of ${\text{S}}_{\text{N}}\text{2}$ reaction shows inversion in configuration.

Interpretation Introduction

(b)

Interpretation:

The structure for the given precursor is to be drawn, paying attention to the stereochemistry.

Concept introduction:

$\text{E2}$ reaction rates are highly sensitive to the strength of the attacking base, whereas $\text{E1}$ reactions are not. Thus, strong bases favor $\text{E2}$ reactions, and weak bases favor $\text{E1}$ reactions. The eliminating group and the leaving group are at anti coplanar conformation in the precursor.