Chapter 8, Problem 8.30AP

Interpretation Introduction

(a)

Interpretation:

The structure of chiral ether ${\text{C}}_{\text{5}}{\text{H}}_{\text{10}}\text{O}$ that has no double bonds is to be drawn.

Concept introduction:

A carbon atom that has four non-equivalent atoms or groups attached to it is known as chiral carbon atom. Chiral carbon centers are also called as asymmetric or stereogenic centers.

The ethers contain $\text{R}-\text{O}-{\text{R}}^{\text{'}}$ functional group in their parent chain. Ethers can be symmetrical or asymmetrical. The name of ether depends upon the groups bonded to oxygen. The groups attached with the oxygen can either be same or different.

Answer to Problem 8.30AP

The structure of chiral ether ${\text{C}}_{\text{5}}{\text{H}}_{\text{10}}\text{O}$ that has no double bonds is shown below.

Explanation of Solution

The given molecular formula of ether is ${\text{C}}_{\text{5}}{\text{H}}_{\text{10}}\text{O}$. The structure of chiral ether is required. Therefore, one carbon atom must possess four non-equivalent atoms or groups attached to it. Let’s consider that one side of an oxygen atom is bonded to a methoxy group. Thus, the remaining molecular formula becomes ${\text{C}}_4{\text{H}}_7$. As the given compound must be chiral and do not possess any double bond. Therefore, cyclopropyl ring with substituted methyl group is assumed to be the other group bonded to an oxygen atom. Hence, the structure of chiral ether ${\text{C}}_{\text{5}}{\text{H}}_{\text{10}}\text{O}$ that has no double bonds is shown below.

Figure 1

Conclusion

The structure of chiral ether ${\text{C}}_{\text{5}}{\text{H}}_{\text{10}}\text{O}$ that has no double bonds is shown in Figure 1.

Interpretation Introduction

(b)

Interpretation:

The structure of chiral alcohol with molecular formula ${\text{C}}_4{\text{H}}_6\text{O}$ is to be drawn.

Concept introduction:

A carbon atom that has four non-equivalent atoms or groups attached to it is known as chiral carbon atom. Chiral carbon centers are also called as asymmetric or stereogenic centers.

The alcohols contain hydroxyl $\left(\text{OH}\right)$ functional group in their parent chain and are named by adding suffix –ol.

Answer to Problem 8.30AP

The structure of chiral alcohol with molecular formula ${\text{C}}_4{\text{H}}_6\text{O}$ is shown below.

Explanation of Solution

The given molecular formula of alcohol is ${\text{C}}_4{\text{H}}_6\text{O}$. The structure of chiral alcohol is required. Therefore, one carbon atom must possess four non-equivalent atoms or groups attached to it. The alcohols contain hydroxyl $\left(\text{OH}\right)$ functional group in their parent chain. Therefore, the remaining structure of the compound with the molecular formula ${\text{C}}_4{\text{H}}_5$ has four carbon atoms and five hydrogen atoms. Let’s consider that the chiral center is bonded to the hydroxyl $\left(\text{OH}\right)$ functional group, hydrogen atom and one methyl group. Therefore, the remaining group has the molecular formula ${\text{C}}_{\text{2}}\text{H}$. Hence, the structure of chiral alcohol with molecular formula ${\text{C}}_4{\text{H}}_6\text{O}$ is shown below.

Figure 2

Conclusion

The structure of chiral alcohol with molecular formula ${\text{C}}_4{\text{H}}_6\text{O}$ is shown in Figure 2.

Interpretation Introduction

(c)

Interpretation:

The structure of vicinal glycol ${\text{C}}_6{\text{H}}_{\text{10}}\text{O}{2}_{}$ that cannot be optically active at room temperature is to be drawn.

Concept introduction:

The alcohols contain hydroxyl $\left(\text{OH}\right)$ functional group in their parent chain and are named by adding suffix –ol. The vicinal glycol refers to an alcohol in which two hydroxyl groups are attached to the adjacent carbon atoms.

Answer to Problem 8.30AP

The structure of vicinal glycol ${\text{C}}_6{\text{H}}_{\text{10}}\text{O}{2}_{}$ that cannot be optically active at room temperature is shown below.

Explanation of Solution

The given molecular formula of vicinal glycol is ${\text{C}}_6{\text{H}}_{\text{10}}\text{O}{2}_{}$. It is given that the compound is not optically active at room temperature. Therefore, it is considered that the hydrogen atoms of hydroxyl groups are intramolecularly connected to each other. The vicinal diols contain two hydroxyl $\left(\text{OH}\right)$ functional groups attached to the adjacent carbon atoms in their parent chain. Therefore, the remaining structure of the compound with the molecular formula ${\text{C}}_4{\text{H}}_8$ has four carbon atoms and eight hydrogen atoms. Thus, the remaining group is $-\text{CH}={\text{CH}}_{\text{2}}$ that is placed on each remaining carbon atom. Hence, the structure of vicinal glycol ${\text{C}}_6{\text{H}}_{\text{10}}\text{O}{2}_{}$ that cannot be optically active at room temperature is shown below.

Figure 3

Conclusion

The structure of vicinal glycol ${\text{C}}_6{\text{H}}_{\text{10}}\text{O}{2}_{}$ that cannot be optically active at room temperature is shown in Figure 3.

Interpretation Introduction

(d)

Interpretation:

The structure of diol ${\text{C}}_4{\text{H}}_{\text{10}}\text{O}{2}_{}$ that exists in only three stereoisomeric forms is to be drawn.

Concept introduction:

The alcohols contain hydroxyl $\left(\text{OH}\right)$ functional group in their parent chain and are named by adding suffix –ol. The diol refers to an alcohol in which two hydroxyl groups are attached to the carbon atoms.

Answer to Problem 8.30AP

The structures of diol ${\text{C}}_4{\text{H}}_{\text{10}}\text{O}{2}_{}$ that exists in only three stereoisomeric forms are shown below.

Explanation of Solution

The given molecular formula of diol is ${\text{C}}_4{\text{H}}_{\text{10}}\text{O}{2}_{}$. It is given that it exists in only three stereoisomeric forms. Therefore, there are two asymmetric carbon atoms, one meso compound and two enantiomers of the given compound. The diols contain two hydroxyl $\left(\text{OH}\right)$ functional groups attached to the carbon atoms in their parent chain. Thus, in the structure, two groups are represented as $\text{H}-\text{C}-\text{OH}$. Therefore, the remaining structure of the compound with the molecular formula ${\text{C}}_2{\text{H}}_6$ has two carbon atoms and six hydrogen atoms that act as two methyl groups. Hence, the structures of diol ${\text{C}}_4{\text{H}}_{\text{10}}\text{O}{2}_{}$ that exists in only three stereoisomeric forms are shown below.

Figure 4

Conclusion

The structures of diol ${\text{C}}_4{\text{H}}_{\text{10}}\text{O}{2}_{}$ that exists in only three stereoisomeric forms are shown in Figure 4.

Interpretation Introduction

(e)

Interpretation:

The structure of diol ${\text{C}}_4{\text{H}}_{\text{10}}\text{O}{2}_{}$ that exists in only two stereoisomeric forms is to be drawn.

Concept introduction:

The alcohols contain hydroxyl $\left(\text{OH}\right)$ functional group in their parent chain and are named by adding suffix –ol. The diol refers to an alcohol in which two hydroxyl groups are attached to the carbon atoms.

Answer to Problem 8.30AP

The structures of diol ${\text{C}}_4{\text{H}}_{\text{10}}\text{O}{2}_{}$ that exists in only two stereoisomeric forms are shown below.

Explanation of Solution

The given molecular formula of diol is ${\text{C}}_4{\text{H}}_{\text{10}}\text{O}{2}_{}$. It is given that it exists in only two stereoisomeric forms. Therefore, there are one asymmetric carbon atom and two enantiomers of the given compound are possible. The diols contain two hydroxyl $\left(\text{OH}\right)$ functional groups attached to the carbon atoms in their parent chain. Thus, in the structure, one group is represented as $\text{H}-\text{C}-\text{OH}$. Therefore, the remaining structure of the compound with the molecular formula ${\text{C}}_3{\text{H}}_8\text{O}$ has three carbon atoms, eight hydrogen atoms and one oxygen atom. Thus, the other two groups are ${\text{CH}}_{\text{2}}\text{OH}$ and ${\text{C}}_2{\text{H}}_5$. Hence, the structures of diol ${\text{C}}_4{\text{H}}_{\text{10}}\text{O}{2}_{}$ that exists in only two stereoisomeric forms are shown below.

Figure 5

Conclusion

The structures of diol ${\text{C}}_4{\text{H}}_{\text{10}}\text{O}{2}_{}$ that exists in only two stereoisomeric forms are shown in Figure 5.

Interpretation Introduction

(f)

Interpretation:

The structures of six epoxides (counting stereoisomers) with the molecular formula ${\text{C}}_4{\text{H}}_8\text{O}$ are to be drawn.

Concept introduction:

The ethers contain $\text{R}-\text{O}-{\text{R}}^{\text{'}}$ functional group in their parent chain and are named by using smaller alkoxy substituent. Ethers can be symmetrical or asymmetrical. The name of ether depends upon the groups bonded to oxygen. The groups attached with the oxygen can either be same or different.

Cyclic ethers with three-membered ring are commonly known as epoxide in which two carbons and one oxygen atom are arranged in cyclic form.

Answer to Problem 8.30AP

The structures of six epoxides (counting stereoisomers) with the molecular formula ${\text{C}}_4{\text{H}}_8\text{O}$ are shown below.

Explanation of Solution

The given molecular formula of the epoxide is ${\text{C}}_4{\text{H}}_8\text{O}$. The molecular formula of epoxide is ${\text{C}}_2{\text{H}}_4\text{O}$. The remaining molecular formula ${\text{C}}_2{\text{H}}_4$ contains two carbon atoms and four hydrogen atoms. One of the hydrogen atoms of each carbon atom in epoxide is substituted by a methyl group. Therefore, the structures of six epoxides (counting stereoisomers) with the molecular formula ${\text{C}}_4{\text{H}}_8\text{O}$ are shown below.

Figure 6

Conclusion

The structures of six epoxides (counting stereoisomers) with the molecular formula ${\text{C}}_4{\text{H}}_8\text{O}$ are shown in Figure 6.