Chapter 10.SE, Problem 26AP

Interpretation Introduction

a)

Interpretation:

The product of the reaction shown is to be predicted.

Concept introduction:

Alcohols gets converted into the corresponding bromides on treatment with HBr in ether solution.

To predict:

The product of the reaction shown.

Answer to Problem 26AP

The product of the reaction shown is

Explanation of Solution

When 1-methylcyclohexanol is treated with HBr, the OH group in it is replaced by the bromine to yield 1-chloro-1-methylcyclohexane and water as products.

Conclusion

The product of the reaction shown is

Interpretation Introduction

b)

Interpretation:

The product of the reaction shown is to be predicted.

Concept introduction:

Alcohols when treated with SOCl₂ yield the corresponding alkyl chlorides along with SO₂ and HCl.

To predict:

The product of the reaction in which 1-butanol reacts with SOCl₂ .

Answer to Problem 26AP

The product of the reaction in which 1-butanol reacts with SOCl₂ is 1-chlorobutane.

Explanation of Solution

When 1-butanol reacts with SOCl₂, the OH group in is replaced by chlorine to yield 1-chlorobutane. SO₂ and HCl are obtained as other products.

Conclusion

The product of the reaction in which 1-butanol reacts with SOCl₂ is 1-chlorobutane.

Interpretation Introduction

c)

Interpretation:

The product of the reaction shown is to be predicted.

Concept introduction:

Cycloalkenes on treatment with NBS in CCl₄ in the presence of light undergo bromination at the allyl position.

To predict:

The product of the reaction shown.

Answer to Problem 26AP

The products of the reaction shown are

Explanation of Solution

NBS is normally used for allylic bromination. The reaction occurs through a radical mechanism. The radical produced by the homolytic cleavage of the C-H bond in the allyl position gets delocalized with the π electrons of the double bond to yield another radical with an odd electron at the junction of the rings. The attack of bromine radical hence leads to two different products as shown.

Conclusion

The products of the reaction shown are

Interpretation Introduction

d)

Interpretation:

The product of the reaction shown is to be predicted.

Concept introduction:

Alcohols give the corresponding bromides as products on treatment with PBr₃ in ether solution.

To predict:

The product of the reaction in which cyclohexanol reacts with PBr₃.

Answer to Problem 26AP

The product of the reaction in which cyclohexanol reacts with PBr₃is

Explanation of Solution

When cyclohexanol is treated with PBr₃, the OH group in it is replaced by the bromine to yield bromocyclohexane.

Conclusion

The product of the reaction in which cyclohexanol reacts with PBr₃ is

Interpretation Introduction

e)

Interpretation:

The products of the reactions shown are to be predicted.

Concept introduction:

Alkyl bromides react with Mg in ether to give Grignard reagents. Grignard reagents when treated with water yield the corresponding alkanes.

To predict:

The products of the reaction shown.

Answer to Problem 26AP

The products of the reaction shown are sec-butyl magnesium bromide (A) and n-butane (B).

Explanation of Solution

sec-butyl bromide when reacted with Mg in ether yields sec-butyl magnesium bromide, a Grignard reagent. The sec-butyl magnesium bromide reacts with water to yield n-butane.

Conclusion

The products of the reaction shown are sec-butyl magnesium bromide (A) and n-butane (B).

Interpretation Introduction

f)

Interpretation:

The products of the reaction shown are to be predicted.

Concept introduction:

Alkyl halides react with Li metal to yield alkyl lithium as product. The alkyllithium when treated with CuI yield Gilmann reagent, lithium dialkylcopper, as the product.

To predict:

The product of the reaction shown.

Answer to Problem 26AP

The products of the reaction shown are N-butyllithium (A) and Lithium n-dibutyl copper (B).

Explanation of Solution

n-Butyl bromide reacts with Li to yield n-butyl lithium and lithium bromide. The n-butyl lithium produced when reacted with CuI yields Lithium n-dibutyl copper as the product.

Conclusion

The products of the reaction shown are N-butyllithium (A) and Lithium n-dibutyl

Interpretation Introduction

g)

Interpretation:

The product of the reaction shown is to be predicted.

Concept introduction:

When alkyl halides are treated with lithium dimethyl copper, the halogens are displaced by an alkyl group and a higher alkane is produced as the product.

To predict:

The product of the reaction in which n-butyl bromide reacts with lithium dimethylcopper.

Answer to Problem 26AP

The product of the reaction in which n-butyl bromide reacts with lithium dimethylcopper is n-pentane.

Explanation of Solution

When n-butyl bromide is treated with lithium dimethylcopper, the bromine is replaced by a methyl group to yield n-pentane as the product.

Conclusion

The product of the reaction in which n-butyl bromide reacts with lithium dimethylcopper is n-pentane.