See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

## Solution: Most Stable Enol Form **Step 1: Identify the parent structure** The given compound contains two carbonyl groups (ketones) in a cyclohexene ring fused to an epoxide. The keto form is the predominant tautomer, but we need to identify which enol form is most stable. **Step 2: Understand enol stability factors** An enol is stabilized by: - Conjugation (extended π-system) - Resonance delocalization - Aromatic character when possible - Fewer steric clashes **Step 3: Analyze each option for enolization** **(A)** Enol-OH on left side, ketone remains on right — creates one C=C but breaks conjugation between the two carbonyls **(B)** Enol-OH on top, ketone below — similar to (A), incomplete conjugation **(C)** Both positions have OH groups and ketones — doesn't show proper enol tautomerization **(D)** Enol-OH on right side with C=C conjugation to the remaining carbonyl on the left - Creates an extended conjugated system: $\text{C}=\text{C}(-\text{OH})-\text{C}=\text{O}$ - The enol-OH is directly conjugated with the adjacent carbonyl - **Resonance stabilization occurs across both groups simultaneously** - Aromatic-like character from the conjugated π-system **Step 4: Conclusion** **Option D** is most stable because the enol form creates a conjugated enone system where the double bond (enol) and carbonyl are directly conjugated, providing maximum resonance stabilization and delocalization of the negative charge on oxygen across both π-bonds.