Fundamentals of Organic ChemistryChemistryGeneral Organic Chemistry
Which of the following compounds are aromatic? (i) (ii) (iii) (iv) (v) (vi) (vii)
Options
- A(i), (iv), (vi), (vii)
- B(i), (iii), (iv), (vii)
- C(iii), (iv), (vi), (vii)
- D(i), (iii), (iv), (vii)
Correct answer
C. (iii), (iv), (vi), (vii)
Step-by-step solution
To determine which compounds are aromatic, we apply Hückel's rule. A compound is aromatic if it is cyclic, planar, completely conjugated, and has (4n + 2) electrons. Let's analyze each compound: (i) 1,2-dimethylenecycloocta-3,5,7-triene: The 8-membered ring is non-planar (tub-shaped) to avoid anti-aromaticity, making the molecule non-aromatic. (ii) [5]radialene: It is cross-conjugated and lacks a continuous cyclic electron system that satisfies Hückel's rule. It is non-aromatic. (iii) Isoquinoline: It is a planar,