Nucleophilic Acyl Substitution == Addition-Elimination?

[justadream]

See thread title. Is that true (for MCAT purposes)?

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[The Brown Knight]

Do you mean electrophilic acyl substitution? an acyl group contains an electron-deficient carbon, so it will be added electrophilically.
An example is the electrophilic aromatic (Friedel-Crafts) acylation of benzene; electrons from a double bond from benzene will attack the carbonyl acyl carbon in an acyl halide and the halide will eventually leave. But now you have a carbocation intermediate, which will then undergo elimination to reform the stable, aromatic ring (this will release a proton).

 

[justadream]

@The Brown Knight

No, I mean nucleophilic acyl substitution (like the picture from wiki)

http://en.wikipedia.org/wiki/Nucleophilic_acyl_substitution

 

[The Brown Knight]

oh gotcha. well this thread makes us both aware that both nucleophilic and electrophilic acyl substitution will involve addition then elimination.

 

[justadream]

@The Brown Knight

Electrophilic acyl substitution is not on the MCAT, right? I thought it wasn't.

 

[The Brown Knight]

I haven't looked at the aamc outlines for o chem. But benzene substitutions (bromination, sulfonylation, alkylation, nitration, etc.) should be there, no?

 

[justadream]

@The Brown Knight

I'm pretty sure benzene reactions are no longer tested and haven't been tested for years.