Chapter 9, Problem 115P

(a)

Interpretation Introduction

Interpretation:

The products of ${\text{S}}_{\text{N}}\text{2/E2}$ reaction of (3S, 4S)-3-bromo-4-methylhexane with methoxide base should be drawn.

Concept Introduction:

For alkyl halide (tertiary, benzylic, and allylic) that can undergo both ${\text{S}}_{\text{N}}\text{2/E2}\text{.}$ and ${\text{S}}_{\text{N}}\text{1/E1}\text{.}$ reaction.

A good nucleophile/strong base favors ${\text{S}}_{\text{N}}\text{2/E2}\text{.}$

In primary alkyl halides substitution take place.

In secondary alkyl halides substitution and elimination take place (strong. bulky bases and high temperatures favor elimination over substitution).

In tertiary alkyl halides only elimination takes place.

Allylic and benzylic halides substitution and elimination takes place (unless they are tertiary).

Tertiary alkyl halides, allylic halides and benzylic halides: substitution and elimination with substitution favored.

(b)

Interpretation Introduction

Interpretation:

The products of ${\text{S}}_{\text{N}}\text{2/E2}$ reaction of (3R, 4R)-3-bromo-4-methylhexane with methoxide base should be drawn.

Concept Introduction:

For alkyl halide (tertiary, benzylic, and allylic) that can undergo both ${\text{S}}_{\text{N}}\text{2/E2}\text{.}$ and ${\text{S}}_{\text{N}}\text{1/E1}\text{.}$ reaction.

A good nucleophile/strong base favors ${\text{S}}_{\text{N}}\text{2/E2}\text{.}$

In primary alkyl halides substitution take place.

In secondary alkyl halides substitution and elimination take place (strong. bulky bases and high temperatures favor elimination over substitution).

In tertiary alkyl halides only elimination takes place.

Allylic and benzylic halides substitution and elimination takes place (unless they are tertiary).

Tertiary alkyl halides, allylic halides and benzylic halides: substitution and elimination with substitution favored.

(c)

Interpretation Introduction

Interpretation:

The products of ${\text{S}}_{\text{N}}\text{2/E2}$ reaction of (3S, 4R)-3-bromo-4-methylhexane with methoxide base should be drawn.

Concept Introduction:

For alkyl halide (tertiary, benzylic, and allylic) that can undergo both ${\text{S}}_{\text{N}}\text{2/E2}\text{.}$ and ${\text{S}}_{\text{N}}\text{1/E1}\text{.}$ reaction.

A good nucleophile/strong base favors ${\text{S}}_{\text{N}}\text{2/E2}\text{.}$

In primary alkyl halides substitution take place.

In secondary alkyl halides substitution and elimination take place (strong. bulky bases and high temperatures favor elimination over substitution).

In tertiary alkyl halides only elimination takes place.

Allylic and benzylic halides substitution and elimination takes place (unless they are tertiary).

Tertiary alkyl halides, allylic halides and benzylic halides: substitution and elimination with substitution favored.

(d)

Interpretation Introduction

Interpretation:

The products of ${\text{S}}_{\text{N}}\text{2/E2}$ reaction of (3R, 4S)-3-bromo-4-methylhexane with methoxide base should be drawn.

Concept Introduction:

For alkyl halide (tertiary, benzylic, and allylic) that can undergo both ${\text{S}}_{\text{N}}\text{2/E2}\text{.}$ and ${\text{S}}_{\text{N}}\text{1/E1}\text{.}$ reaction.

A good nucleophile/strong base favors ${\text{S}}_{\text{N}}\text{2/E2}\text{.}$

In primary alkyl halides substitution take place.

In secondary alkyl halides substitution and elimination take place (strong. bulky bases and high temperatures favor elimination over substitution).

In tertiary alkyl halides only elimination takes place.

Allylic and benzylic halides substitution and elimination takes place (unless they are tertiary).

Tertiary alkyl halides, allylic halides and benzylic halides: substitution and elimination with substitution favored.