[NobodySpecial]

If you start with 2-methylpropane and ethylyne, how can you come up with 1,3-trimethyl-1-proponone? I know this would require multiple steps, but I'm confused as to where to begin. I don't know if I'm fried because the semester is coming to a close, but I'm completely lost. Any help would be appreciated. By the way, I'm trying to figure this out because it was a challenge brought to me by a classmate, this is not for credit.                                                                                                                                                                       

- a confused biology major

[BelarusGirl]

I can't understand what do you mean under 1,3-trimethyl-1-propanone? I'm afraid you've made a mistake or I just can't catch your idea

[movies]

Yeah, "1,3-trimethyl-1-propanone" doesn't make any sense.  Can you draw the compound that you want to make?

[NobodySpecial]

Sorry about that. Evidently my nomenclature is faulty. This is what it looks like:

>---_>==o

I hope this makes sense. It should be an isopropyl connected to the top methyl coming off the  double bond. Also, there should be a CH3 attached to the bottom methyl. Sorry if this is  confusing. I was able to draw the molecule using Chmoogle, but I couldn't save it.

[wereworm73]

You can halogenate one of the 1^o carbons on 2-methylpropane and deprotonate the ethylyne with a strong base (like sodium amide).  The deprotonated ethylyne is a nucleophile and can do an S_N2 reaction on the halogenated 2-methylpropane.  Then add water with HgSO₄ and sulfuric acid to convert the alkyne into a ketone.

Tricky part is halogenating the 1^o carbon instead of the 3^o carbon on 2-methylpropane, but it turns out to be less of a problem using chlorine than, say, bromine...