[quantumnumber]

Hi everyone,

I was thinking of a possible synthesis route for a compound, and in comparison with the one my teacher suggested me, I noticed some unclear points (see the attachment).

His route is shorter, but I think when he uses the base (NaH) in step 2, he could deprotonate also the H_α in relation to ketone group (actually, i think this proton is more acidic). For this reason, I thought of protecting the ketone group with an acetal in order to decrease the acidity of H_α, then going on with the synthesis, and finally deprotect the ketone.

Am I right? Or my teacher's one can work?

Thanks a lot.

[orgopete]

If you wanted to know which acid is a stronger acid, you could look them up. Compare the acidity of cyclohexanone and ethanol in a pKa table. Which is more acidic? However, this is a rather challenging problem and I doubt the relative acidity is the major problem.

[zsinger]

As my mentor told me 10,000,000,000,000 times, Organic Chem is an EXPERIMENTAL science.  Try them, although both should work.  I would go with the one with less overall steps, as yields tend to suffer unless your getting quantitative intermediates (not likely).
             -Zack

[discodermolide]

You could alkylate the enolate with ethylene oxide and work up with allyl bromide, which may just provide the product.

[quantumnumber]

Thanks for all your suggestions. Actually I'm about to take a retrosynthetic anylisis exam and so I guess I just have to indicate a "chemically possible" route, at least theoretically, because I can not check it in the lab

[orgopete]

I thought an aldol condensation reaction would compete with alkylation. I also thought hemiacetal formation would compete, so I didn't like either route. So "chemically possible" would be the operative word here.