Paging Dr. Romano

[super112]

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What in the world is going on in this reaction? You and Feralis are probably the only ones that can make sense of this. I was able to eliminate answers to get this right, but I think I should be a little familiar with the order of mechanism.

I was thinking the 2' amine is basic (b/c of 2 electron donating Ethyls?), so it does an acid/base reaction with COOH...but that leaves me with an ester with a 1' alcohol group at the end. Help please? Answer is C.

 

[aqz]

I believe the 2' amine and the epoxide would first undergo a base-catalyzed epoxide-ring opening. After the ring is opened, the oxygen that was on the epoxide ring now has a negative formal charge and is nucleophilic enough to attack the electrophilic carbonyl on the carboxylic acid. The OH- gets kicked off and probably deprotonates the H on the amine and forms water.

 

[super112]

I believe the 2' amine and the epoxide would first undergo a base-catalyzed epoxide-ring opening. After the ring is opened, the oxygen that was on the epoxide ring now has a negative formal charge and is nucleophilic enough to attack the electrophilic carbonyl on the carboxylic acid. The OH- gets kicked off and probably deprotonates the H on the amine and forms water.

I like it, but there's still a carbonyl remaining from when the epoxide attacked the carbonyl and which then bumped off it's OH. And then there's still the two bromines left over. And that was assuming that the epoxide reaction was faster than an acid/base reaction. All this makes me think that they're being tricky with the question, so I think by saying multistep synthesis, that means there are other reactant steps?

I guess from where you left off, I would add ZnHg, HCl to remove the carbonyl to make it an activating group, and then 2eq of Br2/FeBr3 so that it adds ortho/para with respect to the (...okay damn, I was looking at answer D with methoxy.) Nvm, now we have to somehow get a O-Me out of O-Et). I have no idea at this point haha.

 

[BYU4you]

Dreaded problem from 2009 ADA

 

[aqz]

So they provide you 3 things out of what looks like 10 other things and expect you to know how it works. Seems legit. I wouldn't sweat this one.

 

[BSharp]

For sure narrow it down to C and D to start with because that H on the Nitrogen group is much easier to react than any carbon group on the N.

 

[DAT Destroyer]

What in the world is going on in this reaction? You and Feralis are probably the only ones that can make sense of this. I was able to eliminate answers to get this right, but I think I should be a little familiar with the order of mechanism.

I was thinking the 2' amine is basic (b/c of 2 electron donating Ethyls?), so it does an acid/base reaction with COOH...but that leaves me with an ester with a 1' alcohol group at the end. Help please? Answer is C.

View attachment 192398

Hope you guys enjoy this, feel free to ask questions. Other ways are possible but this is the most direct!

Keep hammering away guys...

Dr. Romano

 

[phillyeagles1]

Wow, thanks for the great explanation Dr. Romano!