Which of the following would you expect to be aromatic?

Question

Quizplus · Accepted Answer

A compound is aromatic if it follows Hückel's rule, which states that a compound must have a planar ring of continuous, overlapping p-orbitals with 4n+2 pi electrons, where n is a non-negative integer. Compound I has only 3 pi electrons, which is not enough to meet the rule. Compound II has a non-planar structure, so it cannot have a continuous ring of overlapping p-orbitals. Compound IV has a sp3 hybridized carbon, which means that it does not have a p-orbital for electron delocalization. Compound III satisfies all the criteria for aromaticity, as it has a planar ring of continuous overlapping p-orbitals with 6 pi electrons, which is 4n+2 where n=1, satisfying Hückel's rule. Therefore, the correct answer is C.

Which of the Following Would You Expect to Be Aromatic