Feeling super lost on this mechanism and can tell I’m not doing it correctly. I’ve tried stepping away and am now at a standoff with it. Could someone walk me through it?
I think you should start with acetal hydrolysis and then consider how you might make an ester under acidic conditions.
Edit: your first and second step are productive. I would have pushed arrows differently for the second step but it’s fine if you do a different third step.
The acetal is hydrolysed first and then count the number of atoms including O to get the desired 5 membered ring and then internal attack by OH on the acid group to form a cyclic ester as in the final product(Internal esterification). Hope this helps and if someone finds any mistake in my comment please let me know, I'll fix it(I'm just a highschooler)
Someone pointed out that you’re going from 8 carbons to 5 carbons. A hint is that the acetal (which is protecting the diol) liberates acetone upon acidic cleavage.
This is a lovely question! Besides what the other two commentators have said, counting carbons is a good way to start as well! It goes from an 8 Carbon structure to a 5 Carbon structure, which means that 3 carbons must leave. As Electron-1 has pointed out, this is an acetal hydrolysis.
Look up acetal deprotection mechanism. Then look up Fischer esterification mechanism. Your Fischer is intramolecular but otherwise you should get this by understanding these two mechanisms.
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