[Rutherford]

This scheme has to be done in reversed order, that's why it gives my a headache.

Hint: A is a gaseous hydrocarbon with the density lower than that of air.

A is probably either C₂H₂ or C₂H₄. In the B reaction scheme, it gives a positive result to the iodoform reaction, so I is probably a methyl secondary alcohol, produced by acidification of B which is an alcoxide.
What reaction of A and B happens at the specified conditions?

[discodermolide]

So F is an ester. N is a tosylate, H a bromide, M an alkene, L an acetylene, start with that.

[Rutherford]

I understand all that, but I need the first reaction. Don't know how to determine anything without it.

Till now, I know that:
-F is an ester (know the structure), N is a tosylate, H a bromide, M an alkene, L an alkyne.
-K is an ester, J an acid salt, I a methyl secondary alcohol, B an alkoxide.

[Rutherford]

I am not sure if the molecular formula for N is correct. The chrysanthemic acid has 10 C atoms, while N has 12, so F will have at least 12, too  .

[discodermolide]

Once again you are not presenting the full information!
Have you read the PDF you posted in the Chem Education forum? If so you would have read that the first reaction was discovered by Favorskii in 1905 http://en.wikipedia.org/wiki/Favorskii_reaction
This is probably your first step.
I also note they present 2 routes to this compound. See if you can work it out now.

[Rutherford]

Sorry for that. I thought that it is more informative than needed to know and I thought first to do one scheme and then the other one. I will try to solve it now when knowing the reaction.

[discodermolide]

Compound E is probably this one.

[Rutherford]

Yes, I finished the first scheme, now I am back to the second one. Why is the acid added to B (which I got that is acetone)?

[discodermolide]

What did you get for A+B :rarrow:L ?

[Rutherford]

Attached. Now I think HBr won't be added according to Markovnikof's rule. As N contains only 2 O atoms, what happened to the -OH group? Was it eliminated with HBr?

[discodermolide]

I think this is H

[Rutherford]

And then the tosilate is introduced. To finish the scheme I need K. I assumed that L is made from acid catalyzed aldol addition of acetone. I finished up with K being the attached compound. Could that be K? If yes, what happens then in reaction with the tosilate and NaOMe?

[discodermolide]

I think this is N:


It's not a tosylate but a sulfone.
Please show me your scheme B I J K

[Rutherford]

Here it is. Is it ok? If yes, what happens with K and N afterwards?

Didn't write that A is acetylene.

[discodermolide]

OK, now what happens to give F?