[spinx625]

“Compound A has molecular formula C7H15Br. Treatment of compound A with sodium ethoxide yields only one elimination product (compound B) and no substitution products. When compound B is treated with dilute sulfuric acid, compound C is obtained, which has molecular formula C7H16O. Draw the structures of compounds A, B, and C.”

From this description I can gather than there’s an E2 elimination and then a hydration. The problem is when I can’t seem to figure out the initial structure (compound A) and thusly the rest of the compounds are marked wrong. I tried a heptane with the Br on the number 1 carbon and a heptane with a Br on the number 2 carbon but both are incorrect. I was wondering if anyone could point me in the right direction on the structure of compound A. Thank you.

[discodermolide]

Try examining the other possible bromoheptane isomers and see what you come up with.

[spinx625]

The thing is I have a minimal number of submissions. I don't think other bromoheptane isomers would make a difference because the first structure I tried was a primary alkyl halide and the second one was secondary. If I put the bromo group anywhere else on the chain it will be secondary or primary also. I was thinking of trying bromocycloheptane but that isn't doesn't give me the correct chemical formula of C7H15Br

[discodermolide]

This is not the case, what about this compound?



it has C₇H₁₅Br, and the bromide is certainly not primary or secondary!

also

[spinx625]

Thank you so much!

[discodermolide]

So what is the structure of compound B?

[orgopete]

Disco is only hinting without hinting at the actual A, B, or C. My hint would be the clues indicate A must have symmetry. I'd try to find a more symmetrical structure.

[spinx625]

So what is the structure of compound B?

This right? The Br and H leave creating an Alkene

[discodermolide]

Sure Br and H must leave to give an alkene, but take into account what Orgopete said.

The two isomers I drew are not the only ones there is another.

[spinx625]

This is the only other structure I can think of for Compound A:


So for compound B, how do I know which Hydrogen is lost?

[discodermolide]

This one?

[spinx625]

So this is structure B?

[discodermolide]

More than likely, what about C?

[spinx625]

Compound C:

[Altered State]

Nope.
Check electrophilic addition to alkenes mechanisms.