Chapter 7.7, Problem 9P

a)

Interpretation Introduction

Interpretation:

More stable carbocation has to be predicted.

Concept Introduction:

Stability of allylic and benzylic cations:

Allylic and benzylic cations have delocalized electrons and possess more stability than other similar carbocations with localized electrons.

The relative stabilities of carbocations are,

$\begin{array}{l}\text{Benzylcation }\text{= }\text{allylcation =}{\text{3}}^{\text{o}}{\text{carbocation > 2}}^{\circ }\text{carbocation >}{\text{1}}^{\circ }\text{carbocation}\text{>}\\ \text{methyl}\text{cation}\text{>}\text{vinyl}\text{cation}\end{array}$

b)

Interpretation Introduction

Interpretation:

More stable carbocation has to be predicted.

Concept Introduction:

Stability of allylic and benzylic cations:

Allylic and benzylic cations have delocalized electrons and possess more stability than other similar carbocations with localized electrons.

$\begin{array}{l}\text{Benzylcation }\text{= }\text{allylcation =}{\text{3}}^{\text{o}}{\text{carbocation > 2}}^{\circ }\text{carbocation >}{\text{1}}^{\circ }\text{carbocation}\text{>}\\ \text{methyl}\text{cation}\text{>}\text{vinyl}\text{cation}\end{array}$

c)

Interpretation Introduction

Interpretation:

More stable carbocation has to be predicted.

Concept Introduction:

Stability of allylic and benzylic cations:

Allylic and benzylic cations have delocalized electrons and possess more stability than other similar carbocations with localized electrons.

The relative stabilities of carbocations are,

$\begin{array}{l}\text{Benzylcation }\text{= }\text{allylcation =}{\text{3}}^{\text{o}}{\text{carbocation > 2}}^{\circ }\text{carbocation >}{\text{1}}^{\circ }\text{carbocation}\text{>}\\ \text{methyl}\text{cation}\text{>}\text{vinyl}\text{cation}\end{array}$