Show how the substituents containing the azo group (N=N) can facilitate both electrophilic and nucleophilic aromatic substitution.
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Verified step by step guidance

1. Step 1: Understand the role of the azo group (N=N) in aromatic substitution. The azo group is an electron-withdrawing group due to the resonance and inductive effects of the nitrogen atoms. This influences the reactivity of the aromatic ring in both electrophilic and nucleophilic aromatic substitution reactions.
2. Step 2: For electrophilic aromatic substitution, the azo group deactivates the aromatic ring by withdrawing electron density. This makes the ring less reactive toward electrophiles. However, the azo group can direct substitution to specific positions (meta-directing) due to its electron-withdrawing nature.
3. Step 3: For nucleophilic aromatic substitution, the electron-withdrawing nature of the azo group increases the susceptibility of the aromatic ring to attack by nucleophiles. This is particularly effective when there are additional electron-withdrawing groups (e.g., fluorine) on the ring, which stabilize the intermediate formed during the substitution process.
4. Step 4: Analyze the reaction provided in the image. The fluorine atom on the aromatic ring is an electron-withdrawing group, and the azo group further enhances the ring's susceptibility to nucleophilic attack. The diethylamine (Et2NH) acts as a nucleophile, replacing the fluorine atom via nucleophilic aromatic substitution.
5. Step 5: The product shows the diethylamino group (Et2N) attached to the aromatic ring, indicating successful nucleophilic substitution. The azo group remains intact, and the tert-butyl carbamate group (O-t-Bu) is unaffected, serving as a protecting group for the azo functionality.

Key Concepts

Azo Group

The azo group (N=N) is a functional group characterized by a nitrogen-nitrogen double bond. It is commonly found in azo compounds, which are often brightly colored and used in dyes. The presence of the azo group can significantly influence the reactivity of aromatic compounds, making them more susceptible to both electrophilic and nucleophilic substitution reactions due to the resonance stabilization it provides.

Electrophilic Aromatic Substitution (EAS)

Electrophilic aromatic substitution is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. The presence of electron-donating groups, such as those attached to an azo group, can enhance the electron density of the aromatic system, making it more reactive towards electrophiles. This process is crucial for synthesizing various aromatic compounds and understanding the reactivity patterns of substituted aromatics.

Nucleophilic Aromatic Substitution (NAS)

Nucleophilic aromatic substitution occurs when a nucleophile attacks an aromatic ring, typically at a carbon atom that is bonded to a leaving group. The presence of electron-withdrawing groups, such as the azo group, can stabilize the negative charge developed during the reaction, facilitating the substitution process. This reaction is particularly important in the synthesis of complex organic molecules and in understanding the behavior of aromatic systems under different conditions.