Which one of the following reactions will not result in the formation of carbon - carbon bond?

Options

A. Reimer - Tieman reaction
B. Friedel Craft's acylation
C. Wurtz reaction
D. Cannizzaro reaction

Explanation

To determine which reaction does not result in the formation of a carbon-carbon bond, let's analyze the given reactions step by step.

### Step 1: Analyze the Riemann-Tiemann Reaction
- **Reaction Overview**: The Riemann-Tiemann reaction involves phenol reacting with chloroform in the presence of a base (like alcoholic KOH).
- **Mechanism**: This reaction generates a dichlorocarbene intermediate (CCl2), which then reacts with phenol to form salicylaldehyde.
- **Carbon-Carbon Bond Formation**: In this process, a new carbon-carbon bond is formed between the phenolic carbon and the carbon from the dichlorocarbene.
- **Conclusion**: This reaction **does** form a carbon-carbon bond.

### Step 2: Analyze Friedel-Crafts Acylation
- **Reaction Overview**: Friedel-Crafts acylation involves the reaction of benzene with an acyl chloride (RCOCl) in the presence of a Lewis acid (like AlCl3).
- **Mechanism**: The acyl chloride forms a carbocation, which then reacts with benzene to form an acylated product.
- **Carbon-Carbon Bond Formation**: Here, a new carbon-carbon bond is formed between the benzene ring and the acyl group.
- **Conclusion**: This reaction **does** form a carbon-carbon bond.

### Step 3: Analyze the Wurtz Reaction
- **Reaction Overview**: The Wurtz reaction involves the coupling of two alkyl halides in the presence of sodium metal and dry ether.
- **Mechanism**: For example, two moles of methyl chloride (CH3Cl) react with sodium to produce ethane (CH3-CH3).
- **Carbon-Carbon Bond Formation**: In this reaction, a new carbon-carbon bond is formed between the two methyl groups.
- **Conclusion**: This reaction **does** form a carbon-carbon bond.

### Step 4: Analyze the Cannizzaro Reaction
- **Reaction Overview**: The Cannizzaro reaction involves aldehydes that lack alpha-hydrogens reacting in the presence of a strong base (like NaOH).
- **Mechanism**: In this reaction, one molecule of the aldehyde is oxidized to a carboxylic acid, while another molecule is reduced to an alcohol.
- **Carbon-Carbon Bond Formation**: Since the aldehyde does not have an alpha-hydrogen, there is no formation of a new carbon-carbon bond in this process.
- **Conclusion**: This reaction **does not** form a carbon-carbon bond.

### Final Conclusion
Based on the analysis of the four reactions, the reaction that does not result in the formation of a carbon-carbon bond is the **Cannizzaro reaction**.

### Answer:
The correct answer is the **Cannizzaro reaction** (Option 4).