[Spiryt]

Hi, I have a problem with homework Our lecturer set us a task to find some information about simple way how to make isobutane from acetone :| I was searching internet but I didn't find anything interesting

[Dan]

Well, you will have to add another carbon... How can you add carbon to carbonyls?

[Spiryt]

Well, you will have to add another carbon... How can you add carbon to carbonyls?

I know only reaction attach halogenchains with Na ... (extending)  :|
So how to swap =O to -CH3 ? :|

[Dan]

So how to swap =O to -CH3 ? :|

I don't know of a way to do that directly, how could you do...

CH₃C(=O)CH₃ ----> CH₃C(OH)(CH₃)CH₃ ?

or

CH₃C(=O)CH₃ -----> CH₃C(=CH₂)CH₃ ?

[Spiryt]

I have an idea but it's to complicated and time-consuming....there can be in two steps:

1) CH3C(=O)CH3 ---H2-> CH3CH2(-OH)CH3 ---HCl-> CH3CH2(-Cl)CH3
      (acetone)                     (2-propanol)               (2-chloropropane)

2) CH3CH2(-Cl)CH3    +    CH3Cl   ---Na-> CH3CH(-CH3)CH3 + CH3CH(-CH3)CH(-CH3)CH3 + CH3CH3
 (2-chloropropane)    (chloromethane)         (isobutane)                  (2,3-dimethylbutane)         (ethane)

But in this reaction there are other compounds besides isobutane     
Help with something simpler . Greets   

[Dan]

The most obvious route I can see is via catalytic hydrogenation of isobutene, which in turn could come from acetone via a Wittig reaction, or from the dehydration of t-butanol which could come from treatment of acetone with a Gringnard reagent or an alkyl lithium. Which is what I was getting at in my second post.

[Spiryt]

"Wittig reaction" ?  sth. new for me.... Can you  . describe a little?

[Borek]

http://en.wikipedia.org/wiki/Wittig_reaction

[ch3m_boy]

Well, you will have to add another carbon... How can you add carbon to carbonyls?

is that an Sn2 rxn?

[Dan]

is that an Sn2 rxn?

It's addition rather than substitution.

[Spiryt]

So it will be sth. like this...:


 

[leakeydong]

First use Witting Reaction to get 2-methylprop-1-ene,
then  use Borane-----BH3.Me2S  to reduce this ene ,and use H2O2 . NaOH aqueous to dispose,then get this alcohol

[HP]

Whats the product of reaction acetone with diazomethane (CH2N2)