Chapter 18.SE, Problem 56GP

Interpretation Introduction

a)

Interpretation:

The products of the reaction shown are to be given.

Concept introduction:

Ethers are cleaved by strong acids. The cleavage takes place either by S_N¹ or S_N² mechanisms, depending upon the structure of the substrate. Ethers with only primary and secondary alkyl groups react by S_N² mechanism. The Br- or I- attacks the protonated ether at the less hindered side to yield a single alcohol and a single alkyl halide. Ethers with a tertiary, benzylic or an allylic group cleave either by S_N¹ or E1 mechanism because these can produce a stable carbocation yielding alkenes and alcohols.

To give:

The products of the reaction shown.

Interpretation Introduction

b)

Interpretation:

The products of the reaction shown are to be given.

Concept introduction:

Treatment of an alkyl halide with thiourea gives alkyl thiourea salt. The salt when hydrolyzed with aqueous bases yields the thiol. The alkyl bromide can be prepared by treating an alcohol with PBr₃.

To give:

The product of the reaction shown.

Interpretation Introduction

c)

Interpretation:

The products of the reaction shown are to be given.

Concept introduction:

Bromine and iodine oxidize thiols to disulfides. The reaction is reversible in nature.

To give:

The product of the reaction shown.

Interpretation Introduction

d)

Interpretation:

The products of the reaction shown are to be given.

Concept introduction:

Sulfides in general are easily oxidized. When treated with H₂O₂ at room temperature they are oxidized to the corresponding sulfoxides.

To give:

The product of the reaction shown.