Which of the following is most reactive towards nucleophilic addition reactions ?

Options

A. `CH_(3)COCH_(3)`
B. `CH_(3)CH_(2)COCH_(2)CH_(3)`
C. `Ph - underset(O)underset(||)(C) - CH_(2)`
D. `Ph - underset(O)underset(||)(C) - Ph`

Explanation

To determine which compound is most reactive towards nucleophilic addition reactions, we need to consider two main factors: the electron deficiency of the carbonyl carbon and the steric hindrance around that carbon.

### Step-by-Step Solution:

1. **Identify the Carbonyl Group**:
- The carbonyl group (C=O) is the functional group involved in nucleophilic addition reactions. The carbon atom in the carbonyl group is electrophilic (electron-deficient) due to the electronegativity of oxygen.

2. **Understand Electron Deficiency**:
- The reactivity of the carbonyl compound towards nucleophiles depends on the electron deficiency of the carbonyl carbon. Electron-withdrawing groups (EWGs) increase the electron deficiency of the carbonyl carbon, making it more susceptible to nucleophilic attack. Conversely, electron-donating groups (EDGs) decrease the electron deficiency.

3. **Consider Steric Hindrance**:
- Steric hindrance refers to the spatial arrangement of atoms around the carbonyl carbon. Bulky groups attached to the carbonyl carbon can hinder the approach of nucleophiles, reducing the reactivity. Therefore, less sterically hindered carbonyl compounds are generally more reactive.

4. **Compare the Given Compounds**:
- Analyze the substituents attached to the carbonyl carbon in the given compounds. Identify which substituents are electron-withdrawing and which are electron-donating. Also, assess the size of these substituents to determine steric hindrance.

5. **Determine the Most Reactive Compound**:
- The compound with the most electron-withdrawing groups and the least steric hindrance will be the most reactive towards nucleophilic addition reactions.

### Conclusion:
After analyzing the substituents and their effects on electron deficiency and steric hindrance, we can conclude which compound is the most reactive towards nucleophilic addition.

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