Chapter 7, Problem 18CTQ

(a)

Interpretation Introduction

Interpretation: The name of the given structure needs to be determined.

  

Concept Introduction: Chair conformation is the most stable conformation of cyclohexane. It is represented as follows:

  

Here, the substituted groups in the chair conformation are represented as follows:

  

The groups showing in straight upward and downward directions are axial and the groups bend slightly right or left are equatorial.

The axial and equatorial groups are represented in the chair conformation as A and E:

  

(b)

Interpretation Introduction

Interpretation: The given structure on the right needs to be completed which is obtained by chair flip.

  

Concept Introduction:After a chair flip, all the axial bonds become equatorial and all the equatorial bonds become axial. But, the groups in the up direction remains upward and groups in down direction remain downward.

Also, if the molecule is cis, it remains cis even after chair flip. The same is the case with trans molecule.

(c)

Interpretation Introduction

Interpretation: The name of the structure formed after the chair flip in part (b) needs to be determined.

Concept Introduction: Chair conformation is the most stable conformation of cyclohexane. It is represented as follows:

  

Here, the substituted groups in the chair conformation are represented as follows:

  

The groups showing in straight upward and downward directions are axial and the groups bend slightly right or left are equatorial.

The axial and equatorial groups are represented in the chair conformation as A and E:

  

(d)

Interpretation Introduction

Interpretation: Whether the two structures are consistent with the given facts about chair flip or not needs to be determined.

Concept Introduction:

The chair conformation of cyclohexane is represented as follows:

  

During the flipping, no bond is break. The numbering in the chair form is represented as follows:

  

During ring flipping, mirror image of the chair conformation is formed.

It is represented as follows: