Which of following statement is/are correct ?

Options

A. In Reimer-Tiemann reaction, dichlorocarbene intermediate is produced.
B. Reimer-Tiemann reaction is example of electrophilic substitution reaction.
C. Highly reactive ring like aniline & highly deactivated ring like nitrobenzene, cyanobenzene do not give Friedel Craft reaction
D. All of these

Answer

To determine which of the statements regarding aromatic compounds are correct, we will analyze each statement one by one based on the information provided in the video transcript.

### Step-by-Step Solution:

1. **Analyze Statement A**:
- The statement claims that in the rheumatoid reaction, a dichlorocarbon intermediate is produced.
- **Explanation**: The rheumatoid reaction involves phenol reacting with chloroform (CHCl3) in the presence of sodium hydroxide (NaOH). During this reaction, a dichlorocarbon intermediate is indeed formed, which is crucial for the subsequent electrophilic substitution that leads to the formation of salicylaldehyde (C7H6O).
- **Conclusion**: Statement A is correct.

2. **Analyze Statement B**:
- The statement claims that the rheumatoid reaction is an example of electrophilic substitution.
- **Explanation**: In the rheumatoid reaction, chloroform acts as an electrophile, and the phenol undergoes electrophilic substitution to form salicylaldehyde. This confirms that the reaction is indeed an electrophilic substitution reaction.
- **Conclusion**: Statement B is also correct.

3. **Analyze Statement C**:
- The statement claims that highly reactive compounds like aniline and highly deactivating groups like nitrobenzene do not undergo Friedel-Crafts acylation.
- **Explanation**: Aniline (which has an amino group, -NH2) is a strong activating group but can be deactivated in Friedel-Crafts reactions due to the presence of the nitrogen lone pair, which coordinates with AlCl3, preventing the acylation. Nitrobenzene, on the other hand, is a strong deactivator and does not undergo Friedel-Crafts acylation due to its electron-withdrawing nature.
- **Conclusion**: Statement C is correct.

4. **Analyze Statement D**:
- The statement claims that compounds like cyanobenzene do not give Friedel-Crafts acylation.
- **Explanation**: Cyanobenzene (C6H5CN) is also a deactivating group due to the presence of the cyano group (-CN), which withdraws electrons from the aromatic ring, making it less reactive towards electrophilic substitution reactions, including Friedel-Crafts acylation.
- **Conclusion**: Statement D is correct.

### Final Conclusion:
All statements A, B, C, and D are correct.