Which of the following is a cyclic ether possessing the characterstics of aromatic compounds?

Options

A.
B.
C.
D.

Answer

D

Explanation

To be aromatic, a monocyclic molecule must be a planer `(4n+2)pi-`electrons molecule. To provide six `pi-`electrons for the ring system, one of the pairs of electrons of the oxygen atom is involved in conjugation with the `pi-`electrons of the ring:

Thus molecule of furan is best regarded as a resonance hybrid of contributing structure `(I)-(IV)`.
It has a resonance energy of `71.1-96.2 kJ mol^(-1)`. Thus, furan is less aromatic than benzene `(RE is 151 kJ mol^(-1))`.