Chapter 25, Problem 25.76P

Interpretation Introduction

(a)

Interpretation:

How to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary is to be shown.

Concept introduction:

Alkynes can be converted to the corresponding alkene either by the treatment of alkali metal (e.g. Na, K) in ammonia called a dissolving metal reduction or by catalytic hydrogenation. The advantage of the catalytic hydrogenation is to form the cis-alkene by the syn-addition of molecular hydrogen, ${\text{H}}_{\text{2}}$ across the $\text{C-C}$ triple bond. The alkynes on treatment with metal in ammonia always give trans-alkene by the anti-addition of the molecular hydrogen, ${\text{H}}_{\text{2}}$ across the triple bond of the alkyne. Alkene on the treatment with peracid the corresponding epoxide is produced. Since the addition of the electron-poor oxygen of the peracid across the double bond of an alkene through a concerted mechanism, the stereochemistry is preserved in the product.

Answer to Problem 25.76P

The synthesis of a given compound from $\text{1-cyclopentylprop-1-yne}$ is given below:

Explanation of Solution

The given synthesis is

The direct conversion is not known. Therefore, the retrosynthesis analysis is done to know the possible route for the synthesis. It is noticed that the cyclopentyl ring and methyl group are trans to each other, thus the alkene results from $\text{1-cyclopentylprop-1-yne}$ must be trans.

Thus the forward reaction is carried out as below:

Since the cyclopentyl ring and methyl group are trans to each other, the alkene results from $\text{1-cyclopentylprop-1-yne}$ must be trans. So the corresponding trans-alkene is produced by the treatment of the ${\text{Na in NH}}_{\text{3}}$. Alkene on the treatment with peracid the corresponding epoxide is produced which is the required product.

Conclusion

It is shown how to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary.

Interpretation Introduction

(b)

Interpretation:

It is to be shown how to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary.

Concept introduction:

Alkynes can be converted to the corresponding alkene either by the treatment of alkali metal (e.g. Na, K) in ammonia or by catalytic hydrogenation. The advantage of the catalytic hydrogenation is to form the cis-alkene by the syn-addition of molecular hydrogen, ${\text{H}}_{\text{2}}$ across the $\text{C-C}$ triple bond. The alkynes on treatment with metal in ammonia always give trans-alkene by the anti-addition of the molecular hydrogen, ${\text{H}}_{\text{2}}$ across the triple bond of the alkyne. Alkene on the treatment with peracid the corresponding epoxide is produced. Since the addition of the electron-poor oxygen of the peracid across the double bond of an alkene through a concerted mechanism, the stereochemistry is preserved in the product.

Answer to Problem 25.76P

The synthesis of the given compound from $\text{1-cyclopentylprop-1-yne}$ is given below:

Explanation of Solution

The given synthesis is

The direct conversion is not known. Therefore, the retrosynthesis analysis is done to know the possible route for the synthesis. It is noticed that the cyclopentyl ring and methyl group are cis to each other, thus the alkene results from $\text{1-cyclopentylprop-1-yne}$ must be cis.

Thus the forward reaction is carried out as below:

Since the cyclopentyl ring and methyl group are cis to each other, the alkene results from $\text{1-cyclopentylprop-1-yne}$ must be cis. So corresponding cis-alkene is produced by the treatment of the ${\text{H}}_{\text{2}}{\text{, Pd, BaSo}}_{\text{4}}$. Alkene on the treatment with peracid the corresponding epoxide is produced which is the required product.

Conclusion

It is shown how to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary.

Interpretation Introduction

(c)

Interpretation:

It is to be shown how to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary.

Concept introduction:

Alkynes can be converted to the corresponding alkene either by the treatment of alkali metal (e.g. Na, K) in ammonia called a dissolving metal reduction or by catalytic hydrogenation. The advantage of the catalytic hydrogenation is to form the cis-alkene by the syn-addition of molecular hydrogen, ${\text{H}}_{\text{2}}$ across the $\text{C-C}$ triple bond. The alkynes on treatment with metal in ammonia always give trans-alkene by the anti-addition of the molecular hydrogen, ${\text{H}}_{\text{2}}$ across the triple bond of the alkyne. Alkyne on catalytic hydrogenation produces the corresponding alkane. The $\text{C-H}$ bond of the tertiary alkane can be brominated under the thermal or photochemical condition via a free radical mechanism.

Answer to Problem 25.76P

The synthesis of the given compound from $\text{1-cyclopentylprop-1-yne}$ is given below:

Explanation of Solution

The given synthesis is

The direct conversion is not known. Therefore, the retrosynthesis analysis is done to know the possible route for the synthesis.

The forward reaction is carried out as:

In the first step the reduction of the alkyne is done to the corresponding alkane by the catalytic hydrogenation as follows:

Finally, the proton of the tertiary carbon is replaced by bromine atom by the treatment of molecular bromine in the presence of light. The tertiary carbon is brominated via a free radical mechanism to form the required product.

Conclusion

It is to be shown how to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary.

Interpretation Introduction

(d)

Interpretation:

How to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary is to be shown.

Concept introduction:

Alkynes can be converted to the corresponding alkene either by the treatment of alkali metal (e.g. Na, K) in ammonia called a dissolving metal reduction or by catalytic hydrogenation. The advantage of the catalytic hydrogenation is to form the cis-alkene by the syn-addition of molecular hydrogen, ${\text{H}}_{\text{2}}$ across the $\text{C-C}$ triple bond. The alkynes on treatment with metal in ammonia always give trans-alkene by the anti-addition of the molecular hydrogen, ${\text{H}}_{\text{2}}$ across the triple bond of the alkyne. The addition of the molecular bromine across the double bond always takes place in trans passion.

Answer to Problem 25.76P

The synthesis of the given compound from $\text{1-cyclopentylprop-1-yne}$ is given below:

Explanation of Solution

The given synthesis is

The direct conversion is not known. Therefore, the retrosynthesis analysis is done to know the possible route for the synthesis.

In the first step the reduction of the alkyne is done to the corresponding alkene by the catalytic hydrogenation as follows:

Finally, the addition of the molecular bromine is done to form the final, required product.

Conclusion

It is shown how to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary.

Interpretation Introduction

(e)

Interpretation:

How to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary is to be shown.

Concept introduction:

Alkynes can be converted to the corresponding alkene either by the treatment of alkali metal (e.g. Na, K) in ammonia called a dissolving metal reduction or by catalytic hydrogenation. The advantage of the catalytic hydrogenation is to form the cis-alkene by the syn-addition of molecular hydrogen, ${\text{H}}_{\text{2}}$ across the $\text{C-C}$ triple bond. The alkynes on treatment with metal in ammonia always give trans-alkene by the anti-addition of the molecular hydrogen, ${\text{H}}_{\text{2}}$ across the triple bond of the alkyne. Since the Diels-Alder reaction is concerted the stereochemistry of the reactant is preserved into the product.

Answer to Problem 25.76P

The synthesis of the given compound from $\text{1-cyclopentylprop-1-yne}$ is given below:

Explanation of Solution

The given synthesis is

The direct conversion is not known. Therefore, the retrosynthesis analysis is done to know the possible route for the synthesis.

In the first step, the reduction of the alkyne is done to the corresponding alkene by the catalytic hydrogenation as follows:

Finally, a Diels-Alder reaction is carried out to produce the required product.

Conclusion

It is shown how to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary.

Interpretation Introduction

(f)

Interpretation:

It is to be shown how to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary.

Concept introduction:

Alkynes can be converted to the corresponding alkene either by the treatment of alkali metal (e.g. Na, K) in ammonia called a dissolving metal reduction or by catalytic hydrogenation. The advantage of the catalytic hydrogenation is to form the cis-alkene by the syn-addition of molecular hydrogen, ${\text{H}}_{\text{2}}$ across the $\text{C-C}$ triple bond. The alkynes on treatment with metal in ammonia always give trans-alkene by the anti-addition of the molecular hydrogen, ${\text{H}}_{\text{2}}$ across the triple bond of the alkyne. Since the Diels-Alder reaction is concerted the stereochemistry of the reactant is preserved into the product.

Answer to Problem 25.76P

The synthesis of the given compound from $\text{1-cyclopentylprop-1-yne}$ is given below:

Explanation of Solution

The given synthesis is

The direct conversion is not known. Therefore, the retrosynthesis analysis is done to know the possible route for the synthesis.

In the first step the reduction of the alkyne is done to the corresponding alkene by the catalytic hydrogenation as follows:

Finally, a Diels-Alder reaction is carried out to produce the required product.

Conclusion

It is shown how to synthesize a given compound from $\text{1-cyclopentylprop-1-yne}$ by using any other reagents necessary.