[mycotheologist]

I'm gonna be giving a 1st year student chemistry tutoring so I'm going over some of his past exam papers to make sure I know all the stuff but I'm already at a question I can't do:

So from the formula, I can see that the degree of unsaturation for the compound is 2. Theres at least one C=C bond in there but the oxygen could either be a carbonyl group or an alcohol. Seeing as it reacts with H2SO4, I assume its an alcohol and the reaction it undergoes is an acid catalysed dehydration of the -OH group. This will yield the alkene. Then ozonolysis breaks the alkene into 2 ketones or aldehydes. Its the final part that has me confused. I don't know what this zinc reduction is and how it could convert ketones or aldehydes into a cyclic ketone.

EDIT: I think I have an idea of whats going on. The original compound is 5-hydroxy-cyclodec-1-ene. Acid catalysed hydrolysis converts it into the cyclodeca-1,5-diene. Ozonolysis produces a 5 carbonyl dialdehyde. The reduction then reduces one of the aldehyde groups and the molecule cyclises. Thats just a guess off the top of my head though, is that correct?

[mycotheologist]

Never mind, I figured it out. The zinc/acetic acid reduction is just to convert the ozonide intermediate into the final ketone/aldehyde. With that in mind its pretty clear what the starting material is (two cyclopentane rings bonded together, with a hydroxyl group attached).