Question

Which of the following compounds are antiaromatic?

• A. (III) and (VI)
• B. (II) and (V)
• C. (I) and (V)
• D. (V) and (VI)

Answer 1

The correct option is A (III) and (VI)

Anti Aromatic compounds are those compounds which satisfy the rules of planarity and fully conjugation of the pi electrons inside the ring but fail to satisfy Huckels rule of $4n+2$ pi electrons.

Anti-aromatic compound contains $4n\pi$ electrons.
The third and sixth compounds are planar and fully conjugated but they do not satisfy the Huckels rule, in the third case no. of pi electrons = 8 and in the sixth case no. of pi electrons = 4. In order to be aromatic, the compounds should have pi electrons = 2,6,10,14......