Predict the products of the following Diels–Alder reactions.
(c)
(d)

Verified step by step guidance

1. Step 1: Identify the diene and dienophile in each reaction. In the first image, the diene is the compound with the CH3O group and two conjugated double bonds, while the dienophile is the compound with the CHO group and a single double bond. In the second image, the diene is the compound with two conjugated double bonds and CH3 groups, while the dienophile is the compound with the CN group and a single double bond.
2. Step 2: Recall the Diels–Alder reaction mechanism. It is a [4+2] cycloaddition reaction where the diene contributes four π-electrons and the dienophile contributes two π-electrons to form a six-membered ring.
3. Step 3: Analyze the electron-withdrawing groups (EWGs) on the dienophile. In the first reaction, the CHO group is an EWG, which enhances the reactivity of the dienophile. In the second reaction, the CN group is an EWG, which also enhances the reactivity of the dienophile.
4. Step 4: Predict the regiochemistry of the reaction. The electron-donating group (CH3O) on the diene will direct the reaction to form the most stable product. Similarly, the CH3 groups on the diene in the second reaction will influence the regioselectivity of the product.
5. Step 5: Draw the product structure. Combine the diene and dienophile to form a six-membered ring. Ensure that the substituents (CH3O, CHO, CH3, CN) are correctly positioned based on the regioselectivity and stereochemistry of the reaction.

Key Concepts

Diels–Alder Reaction

The Diels–Alder reaction is a [4+2] cycloaddition reaction between a conjugated diene and a dienophile, resulting in the formation of a six-membered ring. This reaction is a key method in organic synthesis for constructing cyclic compounds and is characterized by its stereospecificity and regioselectivity, making it a powerful tool for chemists.

Conjugated Dienes

Conjugated dienes are compounds that contain two double bonds separated by a single bond, allowing for resonance stabilization. This structure enhances their reactivity in Diels–Alder reactions, as the electron-rich diene can effectively interact with the electron-deficient dienophile, facilitating the formation of new bonds during the reaction.

Dienophile

A dienophile is a compound that contains a double or triple bond and reacts with a diene in a Diels–Alder reaction. Typically, dienophiles are electron-deficient, which makes them more reactive towards the electron-rich diene. Common examples include alkenes and alkynes with electron-withdrawing groups, which enhance their reactivity in cycloaddition reactions.