[rhyang]

Draw the structure of a hydrocarbon that absorbs two molar equivalents of H2 on catalytic hydrogenation and gives only butanedial on ozonolysis.

I'm totally confused on this one. I don't know where to start, because during ozonolysis don't you get two structures usually? Which separate from the double bond, then become carbonyls? I'm lost, help me please! And thank you!

[rhyang]

Actually I think I figured it out, but can anyone verify for me?

Is the answer a 1,3 cyclobutene? Something like that? This is what I put down so far,

[408]

no, that would form glyoxal.

Need a bigger ring, but you are on the right track with cyclics.

[rhyang]

Hm I'll need a bigger ring? And also, is it supposed to create 2 of those butanedials? So that would mean it should be a cyclooctene? Correct?

[408]

well cyclooctadiene yes, 1,5 to be precise.

[rhyang]

Ah. Thanks for the *delete me* Really appreciate it.