The most stable from trans-1,2-dimethyl cyclohexane is:

Options

A. (a) (1e, 2e)
B. (b) (1a, 2a)
C. (c) (1e, 2a)
D. (d) (1a, 2e)

Answer

To determine the most stable form of trans-1,2-dimethylcyclohexane, we will analyze the two possible conformations: the axial and equatorial positions of the methyl groups.

### Step-by-Step Solution:

1. **Identify the Structure**:
- Trans-1,2-dimethylcyclohexane has two methyl groups attached to the first and second carbon atoms of the cyclohexane ring.

2. **Understand the Conformations**:
- Cyclohexane can adopt different conformations, primarily chair conformations. In these conformations, substituents can occupy axial (pointing up or down) or equatorial (pointing outwards) positions.

3. **Draw the Chair Conformation**:
- Draw the chair conformation of cyclohexane and label the carbons. Place the two methyl groups on carbons 1 and 2.

4. **Analyze Axial vs. Equatorial Positions**:
- **Axial Position**: If both methyl groups are in the axial position (1A, 2A), they will experience steric hindrance due to 1,3-diaxial interactions, which can destabilize the structure.
- **Equatorial Position**: If both methyl groups are in the equatorial position (1E, 2E), they will be further away from each other and other hydrogen atoms on the cyclohexane ring, minimizing steric hindrance.

5. **Compare Stability**:
- The equatorial conformation (1E, 2E) is more stable than the axial conformation (1A, 2A) due to reduced steric hindrance. In the axial position, the methyl groups would be closer to other axial hydrogens, leading to increased steric strain.

6. **Conclusion**:
- The most stable form of trans-1,2-dimethylcyclohexane is the one where both methyl groups are in the equatorial positions (1E, 2E).

### Final Answer:
The most stable form of trans-1,2-dimethylcyclohexane is the equatorial conformation (1E, 2E).

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