The reaction of (Z)-butenedioic acid (fumaric acid) with butadiene sulfone gives only one product. Draw the product of this reaction and explain why only one product forms
To draw the product of the reaction between (Z)-butenedioic acid (fumaric acid) and butadiene sulfone, we first need to understand the reaction mechanism.
The reaction between (Z)-butenedioic acid and butadiene sulfone is an example of a Diels-Alder reaction. Diels-Alder reactions involve a concerted cycloaddition of a diene and a dienophile to form a new cyclic compound. In this case, (Z)-butenedioic acid acts as the dienophile, while butadiene sulfone acts as the diene.
To draw the product, follow these steps:
1. Identify the diene (butadiene sulfone) and the dienophile ((Z)-butenedioic acid).
2. The diene (butadiene sulfone) is a 1,3-diene, meaning that it has two double bonds separated by one single bond. Replace the double bonds with a single bond and add curved arrows showing the formation of a new bond.
3. The reaction forms a new cyclic compound by connecting the two carbon atoms of the diene to the two carbon atoms of the dienophile, resulting in a six-membered ring. Add the double bonds to complete the structure.
Here is the structure of the product:
O
||
C
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H-C==C
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C
||
O
Now, let's explain why only one product forms in this reaction.
The stereochemistry (Z-configuration) of the butenedioic acid (fumaric acid) is responsible for the formation of a single product. The reaction takes place with the diene attacking the dienophile in a concerted manner, resulting in the formation of a cyclic compound. The stereochemistry of the dienophile determines the stereochemistry of the product.
In the case of (Z)-butenedioic acid, both the double bonds are on the same side of the molecule. When the diene approaches the dienophile, it can only attack one face of the molecule due to steric hindrance. As a result, only one stereoisomer is formed.
In contrast, if the dienophile were (E)-butenedioic acid (maleic acid), where the double bonds are on opposite sides of the molecule, two stereoisomers would be formed because the diene could attack from either face.
Therefore, the stereochemistry of the butenedioic acid (fumaric acid) ensures the formation of only one product in the Diels-Alder reaction with butadiene sulfone.
The reaction of (Z)-butenedioic acid (fumaric acid) with butadiene sulfone involves a Diels-Alder reaction. In this reaction, the diene, which is butadiene sulfone in this case, reacts with the dienophile, which is (Z)-butenedioic acid, to form a cyclic product.
The product of this reaction is known as a Diels-Alder adduct. In this case, the Diels-Alder adduct is a cyclic compound that results from the combination of the diene and dienophile.
The specific product formed in this reaction is shown below:
O
/
HOOC - C = C - COOH
\
O
The reason why only one product forms in this reaction is due to the stereoselectivity of the (Z)-butenedioic acid as the dienophile. The (Z)-configuration of the double bonds in (Z)-butenedioic acid imposes a specific orientation requirement during the reaction.
This requirement restricts one of the ends of the diene, butadiene sulfone, to react with the dienophile, leading to the formation of a single product. The reaction proceeds through a concerted process, resulting in the formation of a single stereoisomer.
The reaction is highly regio- and stereoselective, meaning that only specific atoms and specific orientations participate in the reaction, resulting in the formation of a single product.