What's the most appropriate name for this reaction? I recently wrote a test in which I was asked:


  What is this reaction $\ce{CH3CH=CH2 -&gt;[CO + H2O][H+]CH3-CH(COOH)-CH3}$ known as?
  
  
  Wurtz Reaction
  Koch Reaction
  Clemmensen's Reduction
  Kolbe's Reaction
  


My thoughts on this:


It's definitely not Wurtz Reaction, because that reaction eliminates terminal halogens and attaches together two alkyl groups. Also, that reaction needs sodium in dry ethereal medium.
It's definitely not Clemmensen's reduction, because that needs zinc amalgam and acid. (Although acid is present, the reduction won't take place without the zinc, right?).
Now, my options are Koch and Kolbe's reactions. As Koch's reaction (Gatterman-Koch Formylation) adds a carbonyl group, and not a carboxylic acid group, I decide to go with Kolbe's reaction. However, as per Wikipedia, this reaction requires carbon dioxide and sodium phenoxide. The carbon dioxide can be taken care of, by the water gas shift reaction that converts $\ce{CO + H2O-&gt;CO2 + H2}$. But now, there's no sodium phenoxide. What to do now?


Basically, my doubt is whether there's a mistake in my procedure of eliminating the options, or if there's something I'm missing out somewhere which may lead to make a different choice?
As Koch's reaction (Gatterman-Koch Formylation) adds a carbonyl group, and not a carboxylic acid group, I decide to go with Kolbe's reaction.


You started right, and then took the wrong turn ;-)

Under acidic conditions


the proton adds to the $\ce{C=C}$ double bond and gives a secondary cation
the cation reacts with carbon monoxide and yields an acylium cation
the latter reacts with water to result in the formation of a carboxylic acid


The whole process is known as the Koch reaction (without the Gattermann).