The relative reactivities of acyl compound towards nucleophilic substitution are in the order of

Options

A. acyl chloride gt acid anhydride gt ester gt amide
B. ester gt acyl chloride gt amide gt acid anhydride
C. acid anhydride gt amide gt ester gt acyl chloride
D. acyl chloride gt ester gt acid anhydride gt amide

Explanation

To determine the relative reactivities of acyl compounds towards nucleophilic substitution, we need to analyze the structure and basicity of the leaving groups associated with each acyl compound. The acyl compounds in question are acyl chloride, acyl anhydride, ester, and amide.

### Step-by-Step Solution:

1. **Identify the Acyl Compounds**:
- Acyl Chloride (RCOCl)
- Acyl Anhydride (RCO-O-COR')
- Ester (RCOOR')
- Amide (RCONH2)

2. **Identify the Leaving Groups**:
- For acyl chloride, the leaving group is Cl⁻.
- For acyl anhydride, the leaving group is RCOO⁻ (carboxylate ion).
- For ester, the leaving group is RO⁻ (alkoxide ion).
- For amide, the leaving group is NH2⁻ (amide ion).

3. **Analyze the Basicity of Leaving Groups**:
- The reactivity of acyl compounds in nucleophilic substitution reactions is influenced by the basicity of the leaving group. The less basic the leaving group, the more reactive the acyl compound.
- Basicity order (from least basic to most basic):
- Cl⁻ (least basic)
- RCOO⁻ (carboxylate ion)
- RO⁻ (alkoxide ion)
- NH2⁻ (most basic)

4. **Establish the Reactivity Order**:
- Since the leaving group’s basicity inversely affects the reactivity, we can establish the order of reactivity based on the basicity of the leaving groups:
- Acyl Chloride (Cl⁻) > Acyl Anhydride (RCOO⁻) > Ester (RO⁻) > Amide (NH2⁻)

5. **Final Order of Reactivity**:
- Therefore, the relative reactivities of the acyl compounds towards nucleophilic substitution are in the order:
- **Acyl Chloride > Acyl Anhydride > Ester > Amide**

### Conclusion:
The correct answer is: **Acyl Chloride > Acyl Anhydride > Ester > Amide**.