Organic Chemistry

Learn the toughest concepts covered in Organic Chemistry with step-by-step video tutorials and practice problems by world-class tutors.

22. Condensation Chemistry

Conjugate Addition

Once an aldol condensation is completed and we make our enone, an electrophilic carbonyl still remains. Enones specifically have two electrophilic regions on them. I guess that means there's more to the story...



1,2 vs 1,4 Addition

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Alright guys and I want to take this concept one step further and talk about what happens to an unknown after it's been reacted. Can it keep reacting? Turns out it can. So we're gonna talk about what's called conjugate edition of n owns. Remember that unions are those Alfa Beta unsaturated products of Al doll reactions. Okay, cool. So, guys, just before we even get started, I wanna just give you a disclaimer that this topic is called a lot of different things. It's also called 12 versus 14 edition of Unknowns. It's also called Nuclear Filic Edition versus Conjugal edition of carbon yells. So just letting you know that if you find it in your textbook or online, it's got a lot of different names, but it's all the same concept, okay? And what the concept is is that once an outdoor compensation is completed and you make your unknown right, this is your e known in a lecture. Philip Carbon. You'll still remains. Guys, you still have this very partial Positive. So do you think that it has to stop reacting? No, Guys, this thing can react again. Okay? Not only that, not only is it susceptible to nuclear feel like attack the way that a normal carbon Neil would be. But now it actually has a second Electra Filic region. A second region. How does that work? Because if you look at the resonant structure of this molecule, you could always push the electrons up to the right. That would give me a positive and a negative. Okay, that's just a resident structure of a carbon deal. Well, another resident structure would be Now that we have this conjugated portion, we could move this double bond into here, and then I could get the positive out here. That means that I have an Electra Filic region at the to position, if you consider my oxygen to be one. Okay, then at the two position, I have an electric filic region. So I will 12 electra file. But I also have an Electra Electra Filic position at the four. If you're going to consider my oxygen, my one, this would be a one four electric file. So how do I know if I'm attacking with another nuclear file? How do I know if I'm gonna attack the one to or the 14? Okay, Well, the 12 guys is what we call the nuclear Filic edition. This is like something you should be extremely familiar with because we've been doing this. Ah, lot Nuclear Folk Edition now the 14 edition. Because it had to do with a conjugated compound that resonated. This is what we call conjugate edition. Okay, so when I say 12 versus 14 that's the same thing is saying Nuclear Filic versus conjugated Titian quote. So, guys, the answer is it's complicated. It's going to depend on the nuclear files. Okay, So specific nuclear files are gonna favor the nuclear Filic edition with and specific nuclear files other nuclear files are gonna favor with 14 Okay, so let's just hash thes out. Okay? So nuclear filic addition is actually gonna be the minority of reactions, because that continent position is very reactive. So there's really only two reactions that I know of that are gonna want to do this nuclear filic addition on an unknown. Okay. And that's gonna be one green yards. Oh, man, I'm forgetting the end. I'm sorry, guys. Grigg. Nards. Okay. Green yards and two organa lithium. So I'm gonna put our ally. Okay. These are extremely strong nuclear fouls that are gonna go for this site. Just, like always on. We're gonna wind up getting a substituted alcohol, except that the alcohol happens to have a double bond on it. Okay, Conjugate edition is gonna be the majority of additions, guys. So pretty much any other nuclear file besides a grin yard or and we'll get a metallic is going to Or an organ. A lithium is going toe attack here at the four spot. Okay. And what I'm giving you here is specific versions of that. So let's just say you took a generic nuclear file. Well, the product of a generic nuclear file attacking that fourth position would look like this. Okay, notice that there's no more double bond. Okay, No more double bond. All right. It's just gonna be in that four position. Okay? So, guys just, you know, some examples of general nuclear files that could do this would be I mean, there's a lot of them, but specifically, um CN negative is a very common example. Okay. Also, a gilman re agents will be our to C u l i. That's that's also called uh, lithium. Um, Okay. Lithium dial co cooperate or Gilman Regent. Now notice that it's easy to confuse this with these guys, but it's different. The lithium dial co cooperate we've mentioned before is weaker than a normal organo metallic. So I'm gonna expect it toe ad with my conjugate edition. Not with my nuclear Filic edition. And then, honestly, I was just make something up. I mean, there's a lot of different nuclear files that could react there now to specifically that I wanna add to this list that are very important are the new profiles that are gonna make a Michael reaction and historic. And I mean synthesis. Okay, because it turns out that a Michael reaction is gonna be a conjugated edition of an unknown with and in Leeds. Okay, So, Michael, reaction specifically is when you use in in Italy, toe attack. That fourth position. Interesting. Right? So when you use an immolate to attack the fourth position, um, you're gonna wind up getting even more carbons attached to each other. Okay, so when immolate would be specifically a michael reaction. So Michael reaction is a type of conjugate edition, but it's on Lee of Anal It's okay then. We have stork enemy in synthesis. Historic enemies. Synthesis is when you use an enemy. Okay, so remember what an enemy looks like. Let's say a dull bond. Something like this. Okay, I'll make it a really flat cyclo. Heck seen there. Okay, so when youse historic enemy and synthesis again, this could be a nuclear file. You can get electrons going down from the end. It could be a new profile, and it can attack that fourth position. Okay. Now, what's so cool about both of these reactions, guys, is that both the Michael reaction and historic enemy in synthesis make the same exact thing. Guys, they make 15 die carbon eels. Okay, now, 15 die. Carbon eels might not sound like they're very special. It's like, Why is that so special? It's just random carbon is in different places. But if you think about it, guys 15 die carbon deals Air special for one reason. They can psych lies. Okay, They can psych lies and self condensate. Why? Because they like to form six members rings. So the rabbit hole is just getting deeper, guys. Because now I'm telling you that the product oven out all can react with stuff. Now I'm telling you that the product of an algal can react with another Al doll to make an outdoor product that can cycle eyes throughout. All alright, so obviously there's a lot going on. These things can just keep on reacting and reacting, and at some point we've got to call it quits because this could just go on forever. But there are a few more reactions that are specifically gonna need 15 die carbon deals that I want to teach you because you most textbooks or professors don't really put it together. Don't explain how the Michael Reaction and the Stork enemy and synthesis both really do the same exact thing to get to the 15 died car video. All right, So other than that, So you guys understand that your nuclear filic or yeah, your nuclear fuel condition just happens with these two re agents, Everything else adds con you get, let's just add one more. We forgot to put the enemy in here. Enemy is another one we could use and let's just put a random one. So just you guys can see that it's like everything. So, like, for example, end three negative. Okay, So any nuclear file print, any nuclear file could react at that four position and caused that reaction to happen. Okay, Cool. So that being said, let's move on to the next video.