21. Enolate Chemistry:Reactions at the Alpha-Carbon
Beta-Dicarbonyl Synthesis Pathway
21. Enolate Chemistry:Reactions at the Alpha-Carbon
Beta-Dicarbonyl Synthesis Pathway
concept
General Mechanism
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Hey, guys, In this video, I'm going to introduce another very creative way toe. Add our groups to the alfa carbons of your key tones and alga hides. And that's called the Beta die carbon eel. Esther Synthesis pathway crap. Lots of to say. Okay, so what does this mean? Well, we've already been over this guy's how beta die. Carbon eels are unusually acidic due to the incredible stability of the mainly right. So we talked about how the peak a of a normal Alfa Carbon is about 20 but that in a banzai Carbonell compound, it's closer to 10. Okay, so it's very easy to be protein e. Now that's good for us. Because if it's easier to protein eight, that means I have higher yields of the family I'm looking for. Okay, so we're going to use this as an advantage to us that Central carbon we're gonna use it through a multi step synthesis that will consistently add to that Senator Carbon will our groups. Okay, so this is what the pathway looks like. You start off with Ah beta Die, Carbonneau. Esther. Not just you guys know there's two of these that we're gonna be learning about. There's a CDO acidic Esther Aceto Acidic extra. Looks like this. It's basically it's the one that you have drawn here. Okay, It's the one that's already drawn in that box. Okay, but then there's also Milan IQ. Esther? Yeah, Melodic Esther Milan. IQ is the name for three carbon di acid. So it's a three car machine to car oxalic acids. Milan IQ. Esther is just to Esther's. Okay, on both sides. Now, technically, guys, these are groups are all ethel groups. Okay, But that's besides the point. That's not what really what I care about. What I care about is that the shape of these things notice that have two different Esther's. But they're both beta die carbon eel. It's both of them have an Esther with a beta die Carbonell. Okay, so then what you get is that the first step is gonna be an eagle. Late formation. Now, the base we're gonna use we're gonna be careful about it. We wanna sure if we're using an ar oxide base that we're using a base that contains the same our group as the our group in my in my Esther. Does anyone have an idea of why that's important. Guys, you're our groups. Must be the same. Our groups must be the same to avoid. What's it called? Trans A stare ification. And guys, if you're a little bit confused about what transit stratification is or don't remember, just type it into the search bar. The clutch search bar transit certification will pop up, and then you can learn all about it. Okay, so just letting you know you're our group should be the same. So since our is equal toe Ethel, usually the base that we're using is oh, well, o E t negative. Okay, Since I told you that the R is usually a national group, you should be using O E t negative. That's gonna give us in Italy now that Italy could do something very familiar, guys, which is that it can attack an electric file through an essence to reaction or any other mechanism that would, you know, contribute to the attack of an electrified. Okay, so now I have my lecture fall here. Perfect. But we've got a problem. Notice that this part of the compound actually is an Alfa substituted ketone. So if I could find a way to just keep that part of the compound. This would be an office of student ketone. The problem is that I've got all of this crap. I'm trying to use a different color here. The problem is that I've got all of this crap. What I do with this, okay? I don't want that part of the molecule around, but it's there. So if I could figure out a way to get rid of all of this, then I could use this reaction as a means of Alfa substitution. Correct. Well, it turns out that's what the pathway is all about. The pathway is about. You use the beta carbon, he'll get the electrical on there. And then the final two steps are ways to get the, uh oh, the Ester group off. So the first thing we do is what's called an acid catalyzed Esther. Hydraulic assist. Okay, guys, in an acid catalyzed Esther hydraulic assist, you're gonna use acid in water to hide. Relies my Esther, tow a car, broke Cilic acid. Okay, Now, if you haven't learned about your carb oxalic acid derivatives yet, that's okay, But just know that the definition of a car oxalic acid derivative, which is what Esther is is that it could be hydrolyzed to Ah, carb oxalic acid using acid water. Okay, so this hydraulic sis, you don't need to draw the whole mechanism here. You just need to know that your hide relies ing and Esther tocar oxalic acid. Now, what's important about that? Once you do that, guys, then you're gonna have what we call a beta carbonell carb oxalic acid. And what's special about beta Carbonell carb oxalic acids Is that in the presence of heat, they d car box away. So cool. Okay, So, guys, if you don't know what D card box elation is, type it into your clutch search bar. I'm just gonna keep saying that because I got videos for all of this, Okay? It might not be exactly in this part of your textbook, and that's fine, but you can just search for it, okay? Or you might have missed it or what? Who knows? Okay, so you d card box late. That would take this entire thing off, and it's going to just leave what's left over. It's gonna leave your Alfa substitute Carbonell. Plus, you're gonna get co two gas, right cool. So you have your Alfa substitute Carbonell your co two gas. And lo and behold, I used this bizarre four step pathway to produce the same thing that I could have just gotten from an easily calculation. Okay, that I could have just gotten by just putting an anally on the Alfa Carbon and attacking an electro file. But this is a more elegant synthesis because I'm able to use I'm probably gonna be getting what I want in higher yield because it's easier to make my family. I noticed that I have, ah, much more powerful easily that I'm using because my PK of this hydrogen is so much lower, it's much more acidic. Okay, So what I want to do next is go through the specific reactions that aceto acidic Esther and melodic Estrich and go through. So let's go ahead and start off with a CDO acidic Estrich