Chapter 15, Problem 15.20P

Interpretation Introduction

(a)

Interpretation:

The possible structures of the starting materials of the given Diels-Alder product are to be given.

Concept introduction:

In order to find the starting materials of the given compounds follows the rules are given below.

First, label the double bond carbons as $\text{C2}$ and $\text{C3}$ and single bond carbon atoms as $\text{C1}$ and $\text{C4}$. Break the single bond between $\text{C1}$ and $\text{C4}$ and their adjacent dienophile carbon atoms.

In order to complete the diene structure, eliminate the double bonds between $\text{C2}$ and $\text{C3}$ followed by the addition of $\text{C}1-\text{C}2$ and $\text{C3}-\text{C4}$ double bonds.

In order to complete the dienophile structure, add the double bonds between its carbons.

Also, dienophile is substituted with electron withdrawing groups.

Answer to Problem 15.20P

The possible structures of starting materials of given compound can be as follows.

Explanation of Solution

First designate the double bond carbon atoms as $\text{C2}$ and $\text{C3}$ and single bonds as $\text{C1}$ and $\text{C4}$. Now, break the single bonds which make this structure incomplete as shown below

Figure 1

In order to complete the structure of diene, remove the double bonds present between carbons $2$ and $3$ followed by the addition of $\text{C}1-\text{C}2$ and $\text{C3}-\text{C4}$ double bonds.

Figure 2

Finally, complete the dienophile structure by adding the double bonds between carbons.

Figure 3

Similarly, second possibility on the basis of above mentioned steps will be as follows.

First designate the double bond carbons as $\text{C}2\text{\&}\text{C3}$ and single bonds as $\text{C1}\text{\&}\text{C4}$. Now, break the single bonds which make this structure incomplete.

Figure 4

In order to complete the structure of diene, remove the double bonds present between carbons $2$ and $3$ followed by the addition of $\text{C}1-\text{C}2$ and $\text{C3}-\text{C4}$ double bonds

Figure 5

Finally, complete the dienophile structure by adding the double bonds between carbons

Figure 6

Conclusion

The possible starting materials of the given compound are shown in Figure 3 and Figure 6.

Interpretation Introduction

(b)

Interpretation:

The possible structures of the starting materials of the given Diels-Alder product are to be given.

Concept introduction:

First, label the double bond carbons as $\text{C2}$ and $\text{C3}$ and single bond carbons as $\text{C1}$ and $\text{C4}$. Break the single bond between $\text{C1}$ and $\text{C4}$ and their adjacent dienophile carbons.

In order to complete the diene structure, eliminate the double bonds between $\text{C2}$ and $\text{C3}$ followed by the addition of $\text{C}1-\text{C}2$ and $\text{C3}-\text{C4}$ double bonds.

In order to complete the dienophile structure, add the double bonds between its carbons.

Also, dienophile is substituted with electron withdrawing groups.

Answer to Problem 15.20P

The possible structures of starting materials of given compound are shown below.

Explanation of Solution

First designate the double bond carbons as $\text{C2}$ and $\text{C3}$ and single bonds as $\text{C1}$ and $\text{C4}$. Now, break the single bonds which make this structure incomplete as shown below.

Figure 7

In order to complete the structure of diene, remove the double bonds present between carbons $2$ and $3$ followed by the addition of $\text{C}1-\text{C}2$ and $\text{C3}-\text{C4}$ double bonds.

Figure 8

Finally, complete the dienophile structure by adding the double bonds between carbon atoms.

Figure 9

Conclusion

The possible starting materials of given compound are shown in Figure 9.

Interpretation Introduction

(c)

Interpretation:

The possible structures of the starting materials of the given Diels-Alder product are to be given.

Concept introduction:

First, label the double bond carbons as $\text{C}2$ and $\text{C3}$ and single bond carbons as $\text{C1}$ and $\text{C4}$. Break the single bond between $\text{C1}$ and $\text{C4}$ and their adjacent dienophile carbons.

In order to complete the diene structure, eliminate the double bonds between $\text{C2}$ and $\text{C3}$ followed by the addition of $\text{C}1-\text{C}2$ and $\text{C3}-\text{C4}$ double bonds.

In order to complete the dienophile structure, add the double bonds between its carbons.

Also, dienophile is substituted with electron withdrawing groups.

Answer to Problem 15.20P

The possible structures of starting materials of given compound are as follows.

Explanation of Solution

First designate the double bond carbons as $\text{C}2\text{\&}\text{C3}$ and single bonds as $\text{C1}\text{\&}\text{C4}$. Now, break the single bonds which make this structure incomplete.

Figure 10

In order to complete the structure of diene, remove the double bonds present between carbons $2\text{\&}3$ followed by the addition of $\text{C}1-\text{C}2$ and $\text{C3}-\text{C4}$ double bonds.

Figure 11

Finally, complete the dienophile structure by adding the double bonds between carbons.

Figure 12

Conclusion

The possible starting materials of given compound are shown in Figure 12.

Interpretation Introduction

(d)

Interpretation:

The possible structures of the starting materials of the given Diels-Alder product are to be given.

Concept introduction:

First, label the double bond carbons as $\text{C2}$ and $\text{C3}$ and single bond carbons as $\text{C1}$ and $\text{C4}$. Break the single bond between $\text{C1}$ and $\text{C4}$ and their adjacent dienophile carbons.

In order to complete the diene structure, eliminate the double bonds between $\text{C2}$ and $\text{C3}$ followed by the addition of $\text{C}1-\text{C}2$ and $\text{C3}-\text{C4}$ double bonds.

In order to complete the dienophile structure, add the double bonds between its carbons.

Also, dienophile is substituted with electron withdrawing groups.

Answer to Problem 15.20P

The possible structures of starting materials of given compound are as follows.

Explanation of Solution

First designate the double bond carbons as $\text{C}2$ and $\text{C3}$ and single bonds as $\text{C1}\text{\&}\text{C4}$. Now, break the single bonds which make this structure incomplete.

Figure 13

In order to complete the structure of diene, remove the double bonds present between carbons $2\text{\&}3$ followed by the addition of $\text{C}1-\text{C}2$ and $\text{C3}-\text{C4}$ double bonds.

Figure 14

Finally, complete the dienophile structure by adding the double bonds between carbons.

Figure 15

Conclusion

The possible starting materials of given compound are shown in 15.