Question

PRACTICE PROBLEM Two compounds, A and B, have the same molecular formula, C6H8. Both A and B react with two molar equivalents of hydrogen in the presence of platinum to yield cyclohexane. Compound A shows three signals in its broadband decoupled NMR spectrum. Compound B shows only two NMR signals. Compound A shows an absorption maximum at 256 nm, whereas B shows no absorption maximum at wavelengths longer than 200 nm. What are the structures of A and B

Answer 1

See explanation

Step-by-step explanation:

One basic thing that we must keep in mind is that A and B are both dienes.

The NMR spectrum and absorption maxima of A and B indicates that A may be a conjugated diene while B may be an isolated diene.

Remember that conjugated dienes shift the absorption maxima to longer wavelengths due to π - π* transition.

The two structures attached may suffice for compounds A and B