Is My Reasoning for Aromaticity Correct?

[sashab]

Homework Statement

Homework Equations

Huckel's Rule: 4n +2 pi electrons

The Attempt at a Solution

I'm having problems with the last molecule. I said that the first molecule was indeed aromatic because it has 6 pi electrons and obeys the 4n + 2 rule. The second one is not aromatic because it has 16 pi electrons. But for the last molecule, my reasoning for why it's not aromatic is that although it has 6 pi electrons, the electrons in the p orbitals of the carbons from the carbonyls don't occupy the p-orbitals of the oxygen, the two p-orbitals just overlap. So I don't think the p-orbitals of those carbons count towards aromaticity in the ring because those orbitals overlap with the p-orbitals on the oxygens and not the p-orbitals of the adjacent carbons. I was thinking that those p orbitals don't contribute to resonance stabilization in the ring. There are indeed 6 pi electrons, but i don't think the conjugated pi-orbital system criteria is satisfied. Is my reasoning on the right track? Any help would be appreciated. Thanks!

 

[sidarth siddhu]

Homework Statement

View attachment 79483

Homework Equations

Huckel's Rule: 4n +2 pi electrons

The Attempt at a Solution

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The last one is not a planar compound...my textbook says it must be a planar compound to be aromatic.

 

[Suraj M]

The last one is not a planar compound...my textbook says it must be a planar compound to be aromatic.

Could you please state why the last molecule is not planar? it is true that the compound must be planar to be aromatic!

 

[sidarth siddhu]

Maybe becoz of the steric interference between NH group and oxon group it might have been diS placed. .(not so sure abt this)