[gralla55]

What is the product in this reaction?

So obviously, the starting material will lose two hydrogens. The question is, which ones? BuLi is a pretty big molecule, so I'm thinking it will attack only one side of the molecule. This would mean the answer is either A or C. But I can't see the difference between those two. The hybridization of the carbon atoms at the edges should be the same, so that can't be a factor. Any pointers? Thanks alot!

[Doc Oc]

BuLi is actually fairly small.  You're saying A or C, but the products are completely different, so you need to think this through more carefully.  What is BuLi used for?  Use this reactivity to re-think your rationale, otherwise you're just shooting arrows in the dark hoping that you'll hit the bullseye.

[gralla55]

You're right, don't know why I thougth it was so large. I know BuLi is used as a base, but I don't see how the reaction would favor A over C or vice versa.

[Schrödinger]

Why would the answer be A? If H+ is abstracted, then why would there be a +ve charge left behind. That would also eliminate D.

But look at B and C. Isn't there some stabilization factor?

[orgopete]

Look at the reaction below. It is not the answer to your question, but do you understand the reaction of methyllithium with acetylene? The reaction of your bicyclic compound with butyllithium should occur similarly to this reaction with methyllithium. If you do this, perhaps you would think differently about the products that might form.

[gralla55]

Argh, I didn't even se the positive charges in A and D. Well in that case, my original theory was that BuLi was large and could only attack one side of the molecule. Now I'm thinking that the molecule would be more stable if the negative charge was distributed more evenly, which would make B the correct answer?

[Doc Oc]

Yes, B is the one.