Chapter 10, Problem 35P

Draw the major product obtained when each of the following alkyl halides undergoes an E2 reaction:

Interpretation Introduction

Interpretation:

Major product formed when given alkyl halides undergoes E2 reaction has to be drawn.

Concept Introduction:

An E2 reaction is a concerted, one-step reaction in which the proton and the halide ion are removed in the same step.  A strong base favours an E2 reaction.  A high concentration of a base favours an E2 reaction.  If one of the reactants is charged, an E2 reaction will be favoured by the least polar solvent that will dissolve the reactant.  If neither of the reactant is charged an E2 reaction is favoured by the protic polar solvent.  The major product is a stable alkene, unless the reactants are sterically hindered.

Explanation of Solution

The product when given compound undergo E2 addition,

For an E2 reaction major product is the more stable alkene.  The reactant is a secondary alkyl halide, undergo E2 reactions.

Interpretation Introduction

Interpretation:

Major product formed when given alkyl halides undergoes E2 reaction is to be identified.

Concept Introduction:

An E2 reaction is a concerted, one-step reaction in which the proton and the halide ion are removed in the same step.

Explanation of Solution

Chlorocyclohexane is a less stable conformer undergo E2 reaction as $Cl$ is in the axial position and thus makes the reaction slower.

The reactant is a secondary alkyl halide, undergo E2 reactions.

Interpretation Introduction

Interpretation:

Major product formed when given alkyl halides undergoes E2 reaction is to be identified.

Concept Introduction:

An E2 reaction is a concerted, one-step reaction in which the proton and the halide ion are removed in the same step.  A strong base favours an E2 reaction.  A high concentration of a base favours an E2 reaction.  If one of the reactants is charged, an E2 reaction will be favoured by the least polar solvent that will dissolve the reactant.  If neither of the reactant is charged an E2 reaction is favoured by the protic polar solvent.  The major product is a stable alkene, unless the reactants are sterically hindered.

Explanation of Solution

Product of given compound when undergo E2 reaction,

More substituted alkene is more stable therefore should be the major product.

Interpretation Introduction

Interpretation:

Major product formed when given alkyl halides undergoes E2 reaction is to be identified.

Concept Introduction:

An E2 reaction is a concerted, one-step reaction in which the proton and the halide ion are removed in the same step.  A strong base favours an E2 reaction.  A high concentration of a base favours an E2 reaction.  If one of the reactants is charged, an E2 reaction will be favoured by the least polar solvent that will dissolve the reactant.  If neither of the reactant is charged an E2 reaction is favoured by the protic polar solvent.

The major product is a stable alkene, unless the reactants are sterically hindered.

Explanation of Solution

Product of given compound when undergo E2 reaction,

Chloromethyl cyclohexane on E2 reaction gives methylene cyclohexane.  And E2 reaction is regioselective: major product is the more substituted stable alkene.

Interpretation Introduction

Interpretation:

Major product formed when given alkyl halides undergoes E2 reaction is to be identified.

Concept Introduction:

An E2 reaction is a concerted, one-step reaction in which the proton and the halide ion are removed in the same step.  A strong base favours an E2 reaction.  A high concentration of a base favours an E2 reaction.  If one of the reactants is charged, an E2 reaction will be favoured by the least polar solvent that will dissolve the reactant.  If neither of the reactant is charged an E2 reaction is favoured by the protic polar solvent.

The major product is a stable alkene, unless the reactants are sterically hindered.

Explanation of Solution

Product of given compound when undergo E2 reaction,

The reactant is a secondary alkyl halide, undergo E2 reactions.

Interpretation Introduction

Interpretation:

Major product formed when given alkyl halides undergoes E2 reaction is to be identified.

Concept Introduction:

An E2 reaction is a concerted, one-step reaction in which the proton and the halide ion are removed in the same step.  A strong base favours an E2 reaction.  A high concentration of a base favours an E2 reaction.  If one of the reactants is charged, an E2 reaction will be favoured by the least polar solvent that will dissolve the reactant.  If neither of the reactant is charged an E2 reaction is favoured by the protic polar solvent.

The major product is a stable alkene, unless the reactants are sterically hindered.

Explanation of Solution

Product of given compound when undergo E2 reaction,

An E2 reaction is regioselective: major product is the more substituted stable alkene.