Question

Under certain conditions, 1,3-butadiene can function as both a diene and a dienophile. Draw a structural formula for the Diels-Alder adduct formed by reaction of 1,3 -butadiene with itself.

Short answer

Answer: The structural formula of the Diels-Alder adduct is H2C-CH=CH-CH2-CH=CH2, which is a six-membered ring with two double bonds.

Step-by-step solution

Understand the Diels-Alder reaction components

In a Diels-Alder reaction, a conjugated diene reacts with a dienophile to form a cyclic compound. Conjugated dienes contain alternating double and single bonds, while dienophiles have a double or triple bond that reacts with the diene.

Identify the conjugated diene and dienophile

In this case, 1,3-butadiene is both the diene and the dienophile. Its structure is H2C=CH-CH=CH2 (two double bonds with a single bond in between).

Draw the Diels-Alder reaction mechanism

During the Diels-Alder reaction, the double bonds of the diene and dienophile merge and create new single bonds, forming a six-membered ring. The reaction looks like this: \[ \text{H2C=CH-CH=CH2 + H2C=CH-CH=CH2 -> [6] \text{ ring } \]

Draw the final structural formula for the Diels-Alder adduct

The product we get after the reaction is a six-membered ring with two double bonds. The final structure is: \[ \text{H2C-CH=CH-CH2-CH=CH2} \]