16. Conjugated Systems

How would the following substituents affect the rate of a Diels–Alder reaction?

b. an electron-donating substituent in the dienophile

How would the following substituents affect the rate of a Diels–Alder reaction?

a. an electron-donating substituent in the diene

What are the products of the following reactions?

c.

What are the products of the following reactions?

d.

Write a general rule that can be used to predict the major product of a Diels–Alder reaction between an alkene with an electron-withdrawing substituent and a diene with a substituent that can donate electrons by resonance depending on the location of the substituent on the diene.

What two products are formed from each of the following reactions?

b.

The A ring of cortisone (a steroid) is formed by a Diels–Alder reaction using the two reactants shown here. What is the product of this reaction?

The C ring of estrone (a steroid) is formed by a Diels–Alder reaction using the two reactants shown here. What is the product of this reaction?

As many as 18 different Diels–Alder products can be obtained by heating a mixture of 1,3-butadiene and 2-methyl-1,3-butadiene. Identify the products.

Identify the product of the following reaction.

How would the following substituents affect the rate of a Diels–Alder reaction?

c. an electron-withdrawing substituent in the diene

Which dienophile in each pair is more reactive in a Diels–Alder reaction?

1.

Which dienophile in each pair is more reactive in a Diels–Alder reaction?

2.