In nucleophilic acyl substitution, which is the worst leaving group?Select answer from the options belowCH3COO-CH3O-H3C-(CH3)2N-Save for LaterSubmit Answer

Break Down the Problem

1. Identify the potential leaving groups from the options: CH₃COO⁻ (acetate), CH₃O⁻ (methoxide), and H₃C-(CH₃)₂N (a tertiary amine).
2. Assess the stability of each leaving group once they depart from the molecule.

Relevant Concepts

1. A good leaving group is typically a weak base, which can stabilize any negative charge formed after leaving.
2. Common leaving groups include halides, water, and good nucleophiles that can stabilize the resulting charges.

Analysis and Detail

1. CH₃COO⁻ (acetate): This is a resonance-stabilized anion. The charge can be delocalized over the oxygen atoms, making acetate a relatively good leaving group.
2. CH₃O⁻ (methoxide): This is a strong base (the conjugate base of methanol) and has less ability to stabilize the negative charge compared to acetate. Therefore, methoxide is not a good leaving group.
3. H₃C-(CH₃)₂N: This group doesn't readily leave, as it doesn't form a stable anion effectively. While it can release a tertiary amine, which could be relatively stable, the overall leaving capability is poor due to steric hindrance and the basicity of the amine.

Verify and Summarize

• Among the three groups, CH₃O⁻ stands out as the worst leaving group because it is a strong base and cannot stabilize the negative charge effectively once it leaves.
• Therefore, the methoxide ion (CH₃O⁻) is the least favorable to leave in nucleophilic acyl substitution reactions.

Final Answer

The worst leaving group in nucleophilic acyl substitution is CH₃O⁻ (methoxide).