Chapter 3, Problem 71P

(a)

Interpretation Introduction

Interpretation:

The two chair conformers of cis-1-ethyl-3-methylcyclohexane has to be drawn and also the more stable conformer has to be indicated.

Concept introduction:

Conformers: The different spatial arrangements of the atoms that result from rotation about a single bond is called conformational isomers.

Stereoisomerism (or) geometric isomerism: It is known as cis-trans isomerism or E-Z isomerism is a form of stereoisomerism the each of two or more chemical compounds having the same molecular formula but a different geometric arrangement; an unsaturated compound or ring compound in which rotation around a carbon bond is restricted, as in (cis) and (trans) configurations know as geometric isomerism.

Relative stability of cyclohexane: The most stable conformation of cyclohexane is the chair shown to the right, the respective carbon (-C-C-) bonds are it close to (109.5⁰), it is almost free of angle strain, it is also a fully staggered conformation and so is free of torsional strain.  So the chair conformation is the most stable conformation.

(b)

Interpretation Introduction

Interpretation:

The two chair conformers of trans-1-ethyl-2-isopropylcyclohexane has to be drawn.

Concept introduction:

Conformers: The different spatial arrangements of the atoms the result from rotation about a single bond is called conformational isomers.

Stereoisomerism (or) geometric isomerism: It is known as cis-trans isomerism or E-Z isomerism is a form of stereoisomerism the each of two or more chemical compounds having the same molecular formula but a different geometric arrangement; an unsaturated compound or ring compound in which rotation around a carbon bond is restricted, as in (cis) and (trans) configurations know as geometric isomerism.

Relative stability of cyclohexane: The most stable conformation of cyclohexane is the chair shown to the right, the respective carbon (-C-C-) bonds are it close to (109.5⁰), it is almost free of angle strain, it is also a fully staggered conformation and so is free of torsional strain.  So the chair conformation is the most stable conformation.

(c)

Interpretation Introduction

Interpretation:

The two chair conformers of trans-1-ethyl-2-methylcyclohexane has to be drawn and also the more stable conformer has to be indicated.

Concept introduction:

Conformers: The different spatial arrangements of the atoms the result from rotation about a single bond is called conformational isomers.

Stereoisomerism (or) geometric isomerism: It is known as cis-trans isomerism or E-Z isomerism is a form of stereoisomerism the each of two or more chemical compounds having the same molecular formula but a different geometric arrangement; an unsaturated compound or ring compound in which rotation around a carbon bond is restricted, as in (cis) and (trans) configurations know as geometric isomerism.

Relative stability of cyclohexane: The most stable conformation of cyclohexane is the chair shown to the right, the respective carbon (-C-C-) bonds are it close to $\left(\text{109}\text{.5°}\right)\text{,}$ it is almost free of angle strain, it is also a fully staggered conformation and so is free of torsional strain.  So the chair conformation is the most stable conformation.

(d)

Interpretation Introduction

Interpretation:

The two chair conformers of cis-1,2-diethylcyclohexane has to be drawn.  Also mention the stable one.

Concept introduction:

Conformers: The different spatial arrangements of the atoms the result from rotation about a single bond is called conformational isomers.

Stereoisomerism (or) geometric isomerism: It is known as cis-trans isomerism or E-Z isomerism is a form of stereoisomerism the each of two or more chemical compounds having the same molecular formula but a different geometric arrangement; an unsaturated compound or ring compound in which rotation around a carbon bond is restricted, as in (cis) and (trans) configurations know as geometric isomerism.

Relative stability of cyclohexane: The most stable conformation of cyclohexane is the chair shown to the right, the respective carbon (-C-C-) bonds are it close to (109.5⁰), it is almost free of angle strain, it is also a fully staggered conformation and so is free of torsional strain.  So the chair conformation is the most stable conformation.

(e)

Interpretation Introduction

Interpretation:

The two chair conformers of cis -1-ethyl-3-isopropylcyclohexane has to be drawn.  Also mention the stable one.

Concept introduction:

Conformers: The different spatial arrangements of the atoms the result from rotation about a single bond is called conformational isomers.

Stereoisomerism (or) geometric isomerism: It is known as cis-trans isomerism or E-Z isomerism is a form of stereoisomerism the each of two or more chemical compounds having the same molecular formula but a different geometric arrangement; an unsaturated compound or ring compound in which rotation around a carbon bond is restricted, as in (cis) and (trans) configurations know as geometric isomerism.

Relative stability of cyclohexane: The most stable conformation of cyclohexane is the chair shown to the right, the respective carbon (-C-C-) bonds are it close to (109.5⁰), it is almost free of angle strain, it is also a fully staggered conformation and so is free of torsional strain.  So the chair conformation is the most stable conformation.

(f)

Interpretation Introduction

Interpretation:

The two chair conformers of cis-1-ethyl-4-isopropylcyclohexane has to be drawn.

Concept introduction:

Conformers: The different spatial arrangements of the atoms the result from rotation about a single bond is called conformational isomers.

Stereoisomerism (or) geometric isomerism: It is known as cis-trans isomerism or E-Z isomerism is a form of stereoisomerism the each of two or more chemical compounds having the same molecular formula but a different geometric arrangement; an unsaturated compound or ring compound in which rotation around a carbon bond is restricted, as in (cis) and (trans) configurations know as geometric isomerism.

Relative stability of cyclohexane: The most stable conformation of cyclohexane is the chair shown to the right, the respective carbon (-C-C-) bonds are it close to (109.5⁰), it is almost free of angle strain, it is also a fully staggered conformation and so is free of torsional strain.  So the chair conformation is the most stable conformation.