DAT Destroyer 2014 OChem Question #56

[woosh]

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once the enamine is formed, how does the product form from reacting with C2H5I/H2O? what mechanism does enamine go through? (refer to image)

 

[Dotoday]

Beta carbon functions as a nucleophile to attack c2H5 I

 

[woosh]

Beta carbon functions as a nucleophile to attack c2H5 I

Wouldn't it be the alpha carbon that would function as a nucleophile to attack C2H5I?
Plus, what would the water molecules be doing in order to form that carbonyl group?

 

[Dotoday]

No. If you look at the resonance form, the beta carbon will be negative.

 

[Jay20155555]

the resonance form I get has the alpha carbon as negative

 

[MrSnuggles]

Not sure if this is completely accurate but here's what I see. The last step is a bit simplified but the basic idea is water attacks the carbocation and deprotonates to form an alcohol. The amine can take an H off a H2O, making it a good leaving group. The attached hydroxide group can then form a carbonyl, kicking off the amine. And yes, it's the alpha carbon that acts as a nucleophile when it attacks the ethyl iodide.

 

[DAT Destroyer]

 

[dentallyfe]

View attachment 194869

What is this reaction called? Is this a special kind of Addition or is it something else?

 

[Elisonen]

What is this reaction called? Is this a special kind of Addition or is it something else?

This is in the 2017 Destroyer question 71. Check out masterorganicchemistry (subscription required). This reaction is called "Alkylation of enamines with alkyl halides", and there, you will see such an examples. Check example 3.