Which of the following reactions will not give a four-membered cyclic compound ?

Options

A.
B.
C.
D. d.

Answer

To determine which of the given reactions will not yield a four-membered cyclic compound, we will analyze each reaction step by step.

### Step 1: Analyze Reaction A
- **Starting Material**: A compound containing an acetic hydrogen.
- **Reagent**: Sodium ethoxide (NaOEt).
- **Mechanism**: NaOEt abstracts the acetic hydrogen, forming a carbanion. This carbanion attacks another carbon atom, leading to the formation of a cyclic compound.
- **Conclusion**: This reaction will yield a four-membered cyclic compound.

### Step 2: Analyze Reaction B
- **Starting Material**: Another compound with acetic hydrogen.
- **Reagent**: Sodium ethoxide (NaOEt).
- **Mechanism**: Similar to Reaction A, NaOEt abstracts the acetic hydrogen, forming a carbanion. This carbanion attacks a carbon containing bromine, leading to the formation of a cyclic compound.
- **Conclusion**: This reaction will also yield a four-membered cyclic compound.

### Step 3: Analyze Reaction C
- **Starting Material**: A compound that can undergo a cyclization reaction.
- **Mechanism**: The reaction involves the formation of a cyclic compound through the attack of one carbon on another, leading to the formation of a cyclopropane.
- **Conclusion**: This reaction will yield a four-membered cyclic compound (cyclopropane).

### Step 4: Analyze Reaction D
- **Starting Material**: A compound that can form free radicals.
- **Mechanism**: The free radicals combine to form a bond, resulting in the formation of a ring structure.
- **Conclusion**: This reaction will also yield a four-membered cyclic compound (cyclobutane).

### Final Conclusion
After analyzing all the reactions, we find that:
- Reactions A, B, and D yield four-membered cyclic compounds.
- Reaction C is the only one that does not yield a four-membered cyclic compound.

### Answer
The reaction that will not give a four-membered cyclic compound is **C**.