enamine alkylation

[bigballer27]

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wtf is this lol i had a question about it on a practice test i took

i know that a ketone + 2ary amine gives an enamine, but how do you alkylate it?

also, how specifically should we be studying mechanisms? i know some and can figure some out by common sense, but overall, my ochem is weak so im just trying to get a basis of reactions for now. Do they test you on specific mechanisms ever, or for the reactions, it is ok to know reactants products, solvents, and maybe a general understanding as to why they happen

 

[RogueUnicorn]

wow.. i have absolutely no idea what the heck that is. are you sure the passage didn't give you a clue as to what it was?

 

[nwdmd]

So, your enamine should have a nitrogen with a lone pair (N: )

If you see a nitrogen with a lone pair, know that it is a fairly good Nucleophile

This lone pair will react with an alkyl halide, attacking the Carbon and displacing the halide (good leaving groups).

The end product is the alkyl group attached to the N of the enamine.

Regarding general Ochem mech: When you see a nitrogen, look at the number of bonds (5e- available, one shared per bond) and if applicable.. imagine a fatty lone pair on it (i.e. 2e- not involved in bond).. this characteristic makes it a good nucleophile..

What resources are you using for Ochem review?

 

[bigballer27]

i just spent another 15 min trying to figure it out but i think i got it
Sorry, bleargh i was kinda confused and misunderstood the question lol

the 2ary amine had a double bond at the B-carbon, so that d.b acted as a nucleophile to attack CH3-I, adding a methyl group Beta to the nitrogen, because I is a good leaving group

so i guess it was a wierd one, not realy an alkylation in the sense i thought it would be, but yes, there were clues given in the passage, i just didn't read it properly(shocker!)


nwdmd, im using princeton review for ochem and so far its been good, i just have such a weak background in ochem that everything sounds confusing. This question came from Princeton Review practice test #2...