Chapter 10.5, Problem 12P

(a)

Interpretation Introduction

Interpretation:

The given reaction whether undergoes E1 or E2 elimination has to be predicted.  Major product of the reaction has to be drawn.

Concept Introduction:

• Elimination reaction is a reaction in which an atom or group of a molecule is eliminated and a double bond is formed.
• This type of reaction primarily occur in alkyl/aryl halides.
• Elimination reactions are of two types – E1 elimination and E2 elimination.
• E1 elimination involves formation of carbocation by dissociation of alkyl halide in one step.  In next step removal of base by proton takes place.
•  E2 elimination is a concerted reaction and involves formation of transition state in which both proton and halide are removed in one single step.
• E2 elimination follows Zaistev’s rule that the major product is usually the most substituted alkene.  Thus E2 reaction is regioselective.  If the leaving group is too weak then least substituted alkene is formed.
• Primary and secondary halides undergo E2 elimination whereas tertiary halides undergo E1 elimination as tertiary carbocation formed is more stable.
• Allylic and benzylic halides undergo both E1 and E2 reactions.
• Presence of high concentration of strong base favours E2 reaction.
• Presence of weak base favours E1 reaction.

(b)

Interpretation Introduction

Interpretation:

The given reaction whether undergoes E1 or E2 elimination has to be predicted.  Major product of the reaction has to be drawn.

Concept Introduction:

• Elimination reaction is a reaction in which an atom or group of a molecule is eliminated and a double bond is formed.
• This type of reaction primarily occur in alkyl/aryl halides.
• Elimination reactions are of two types – E1 elimination and E2 elimination.
• E1 elimination involves formation of carbocation by dissociation of alkyl halide in one step.  In next step removal of base by proton takes place.
•  E2 elimination is a concerted reaction and involves formation of transition state in which both proton and halide are removed in one single step.
• E2 elimination follows Zaistev’s rule that the major product is usually the most substituted alkene.
• Primary and secondary halides undergo E2 elimination whereas tertiary halides undergo E1 elimination as tertiary carbocation formed is more stable.
• Allylic and benzylic halides undergo both E1 and E2 reactions.
• Presence of high concentration of strong base favours E2 reaction.
• Presence of weak base favours E1 reaction.

(c)

Interpretation Introduction

Interpretation:

The given reaction whether undergoes E1 or E2 elimination has to be predicted.  Major product of the reaction has to be drawn.

Concept Introduction:

• Elimination reaction is a reaction in which an atom or group of a molecule is eliminated and a double bond is formed.
• This type of reaction primarily occur in alkyl/aryl halides.
• Elimination reactions are of two types – E1 elimination and E2 elimination.
• E1 elimination involves formation of carbocation by dissociation of alkyl halide in one step.  In next step removal of base by proton takes place.
•  E2 elimination is a concerted reaction and involves formation of transition state in which both proton and halide are removed in one single step.
• E2 elimination follows Zaistev’s rule that the major product is usually the most substituted alkene.
• Primary and secondary halides undergo E2 elimination whereas tertiary halides undergo E1 elimination as tertiary carbocation formed is more stable.
• Allylic and benzylic halides undergo both E1 and E2 reactions.
• Presence of high concentration of strong base favours E2 reaction.
• Presence of weak base favours E1 reaction.

(d)

Interpretation Introduction

Interpretation:

The given reaction whether undergoes E1 or E2 elimination has to be predicted.  Major product of the reaction has to be drawn.

Concept Introduction:

• Elimination reaction is a reaction in which an atom or group of a molecule is eliminated and a double bond is formed.
• This type of reaction primarily occur in alkyl/aryl halides.
• Elimination reactions are of two types – E1 elimination and E2 elimination.
• E1 elimination involves formation of carbocation by dissociation of alkyl halide in one step.  In next step removal of base by proton takes place.
•  E2 elimination is a concerted reaction and involves formation of transition state in which both proton and halide are removed in one single step.
• E2 elimination follows Zaistev’s rule that the major product is usually the most substituted alkene.
• Primary and secondary halides undergo E2 elimination whereas tertiary halides undergo E1 elimination as tertiary carbocation formed is more stable.
• Allylic and benzylic halides undergo both E1 and E2 reactions.
• Presence of high concentration of strong base favours E2 reaction.
• Presence of weak base favours E1 reaction.

(e)

Interpretation Introduction

Interpretation:

The given reaction whether undergoes E1 or E2 elimination has to be predicted.  Major product of the reaction has to be drawn.

Concept Introduction:

• Elimination reaction is a reaction in which an atom or group of a molecule is eliminated and a double bond is formed.
• This type of reaction primarily occur in alkyl/aryl halides.
• Elimination reactions are of two types – E1 elimination and E2 elimination.
• E1 elimination involves formation of carbocation by dissociation of alkyl halide in one step.  In next step removal of base by proton takes place.
•  E2 elimination is a concerted reaction and involves formation of transition state in which both proton and halide are removed in one single step.
• E2 elimination follows Zaistev’s rule that the major product is usually the most substituted alkene.
• Primary and secondary halides undergo E2 elimination whereas tertiary halides undergo E1 elimination as tertiary carbocation formed is more stable.
• Allylic and benzylic halides undergo both E1 and E2 reactions.
• Presence of high concentration of strong base favours E2 reaction.
• Presence of weak base favours E1 reaction.

(f)

Interpretation Introduction

Interpretation:

The given reaction whether undergoes E1 or E2 elimination has to be predicted.  Major product of the reaction has to be drawn.

Concept Introduction:

• Elimination reaction is a reaction in which an atom or group of a molecule is eliminated and a double bond is formed.
• This type of reaction primarily occur in alkyl/aryl halides.
• Elimination reactions are of two types – E1 elimination and E2 elimination.
• E1 elimination involves formation of carbocation by dissociation of alkyl halide in one step.  In next step removal of base by proton takes place.
•  E2 elimination is a concerted reaction and involves formation of transition state in which both proton and halide are removed in one single step.
• E2 elimination follows Zaistev’s rule that the major product is usually the most substituted alkene.
• Primary and secondary halides undergo E2 elimination whereas tertiary halides undergo E1 elimination as tertiary carbocation formed is more stable.
• Allylic and benzylic halides undergo both E1 and E2 reactions.
• Presence of high concentration of strong base favours E2 reaction.
• Presence of weak base favours E1 reaction.