The Law Posted March 3, 2010 Report Share Posted March 3, 2010 If benzaldehyde and 2-methylcyclohexanone are placed together in the presence of an acid, and a mixed aldol condensation takes place, which one will serve as the nucleophile? A) The aldehyde to give a single product The ketone to give two products C) Both the aldehyde and the ketone to give two different products D) Neither Answer: B --- So I got the answer, but thinking about it - I don't understand how the reaction would really proceed (given that it is acid catalyzed and not base, and I'm not sure what the mechanism would look like). I'm also not sure why there are two products. Basically, I know it can't be 2-methylcycolhexanone because there are no alpha carbons in this molecule to do the attacking! How would the acid catalyzed mechanism proceed? Is it the ketone or the aldehyde being protonated? I looked in TPR and EK, they mention aldols can be acid catalyzed but don't show the mechanism. Link to comment Share on other sites More sharing options...
The Ace of Spades Posted March 3, 2010 Report Share Posted March 3, 2010 In the acid-catalyzed reaction, the aldehyde is protonated, creating a polarized carbonyl which is more susceptible to nucleophilic attack at the carbon. Link to comment Share on other sites More sharing options...
The Law Posted March 3, 2010 Author Report Share Posted March 3, 2010 In the acid-catalyzed reaction, the aldehyde is protonated, creating a polarized carbonyl which is more susceptible to nucleophilic attack at the carbon. Would water then remove an alpha-hydrogen from the ketone? I thought this might be the case, but wasn't sure how the nucleophile would be generated. Link to comment Share on other sites More sharing options...
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