Dicarbonyl compounds have the ability to self-condensate through cyclization. When a diketone or dialdehyde self-condensate, the resulting product is called a cyclic enone.
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Hey, everyone. In this next page, we're gonna be focusing on a special type of condensation called an intra molecular condensation. Alright, guys, So it gets a little bit more complicated, right? So die Carbonell compounds have the ability to self condensate through cycle ization if it will generate a five or six members ring. Okay, here's the deal. Any ring below five members 43 way too unstable to psych lies on its own. Okay, you're gonna need to put a lot of energy into that system to make it happen. So in order for these reactions to be favorable, we're gonna try to make five and six members rings. Okay, that's actually gonna be a theme later on, when we saw what other reactions that compensation products can undergo. Okay, so here I've got this Dikky tone right now. This could happen to die. Esther's Dikky tones. Whatever die Aldo hides, the biggest point here is that when you make your email late, you wanna make your easily in a place where if you attack the carbonell, you'll make either five or six member brain. So let me ask you a question. I've actually got four different positions that could make immolates here. I've got position one position to position three and position for Okay. Now, you guys understand that three and four are the same thing as one and two, so I'm gonna erase them, because that's just distracting me. So I literally I just have a choice between Do I put the Emily on carbon one or on carbon, too? They both have Alfa hydrogen, so I could definitely get in late there. The question is, you're gonna the real way that you decide. This is you decide by the ring that you could make after you cycle eyes. Okay, so let's look at, For example, in late two, if I were to put my easily on carbon too, then it would attack this carbon. You'll hear. Okay. How big would that ensuing ring be? Well, this being my first my nuclear fall always gets the first test carbon in the count. So should be one, 234 Okay, you always count from nuclear followed toe Electra file. Is that big enough? No way. Let's talk about one. So if I were to make it on one, I mean it can't attack that one. That's way too close. It would attack this carbon deal. So then let's count. Let's see if it's the right size. 12345 guys, that is a lot better. That's a six carbon chain that is going to connect between one and the six making a six member ring. Okay, so that any O. E. T. Is going to specifically making Emily here so that it can psych lies on its own. Okay, Now the mechanism is just gonna be what you expect for any outdoor reaction, you would kick up the electrons to the O H. I mean to the oh, and then it would protein e. Okay, so what we could do here is what I like to do is, if we already know it's gonna be a six member ring, let's just draw a six member bring and then let's just add the group's okay Now, from lots of years of experience, I know that it's actually gonna be easiest to number this ring If I start at I guess the top left corner and I worked my way around counterclockwise. So 123456 Literally Guys, this is just me trying toe. Make it look as pretty as possible. You could have numbered it however you want. As long as your numbers in our in order, it doesn't matter. Okay? The only thing you can do is like 13 57 Whatever. Okay, so what am I missing? What groups do I need? Okay, so it looks like I'm missing a key tone on to, so I'm gonna put that there. What else I'm missing? It looks like I'm missing. Um, some stuff on six. What? I am missing on six. Could you guys tell me exactly think about it. They call exactly what's not on this chain on this ring. I'm missing an O. H. Right. Because we said that it's gonna prove me I'm missing anything else. I'm also missing a method, right? Because, look, this method was not part of the ring. It's just extra. So there we go. Now we have it drawn correctly. This is called what? It's the name of this product. This is our beta hydroxy carbon. Neil, you're getting professional at this at this point. Okay, but what do we know about beta hydroxy carbon meals? They love to dehydrate, right? So we're gonna dehydrate this bad boy, and we're gonna dehydrate between the Alpha and the beta. So what this is gonna make as a final answer is I'm going to get what we call a cyclic n on. And, guys, this is gonna be highly favored, because that's really stable. Okay, so you're gonna get a cyclic unknown, and that's you get when you have basically an intra molecular reaction, That's an out. All this would be specifically an intra molecular out. All right? You might say, Johnny, how do you know it was Al doll? Because its key tones or al diets, okay. And you're gonna get a cyclic, you know? Okay, So in the next video, I'm gonna show you what happens for intra molecular connotations of Esther's
When a diester self-condensates, the resulting product is called a cyclic β-ketoester.
This is known as a Dieckmann Condensation or Intramolecular Claisen
Diesters (Dieckmann Condensation)
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So guys wanna die, Esther cycle ises and self condensates. The product is gonna be a cyclic beta keto, ester. And this just makes sense because beta Keto Ester is always the product of a place in. But now it's gonna be a ring because it's intra molecular. Now, chemist just had to make this overly complicated. And apparently the guy that discovered this specific cycle ization was called Dykeman. So this is also called a Dyckman condensation. But don't get too hung up on the name, because really, all it is is an intra molecular clasing. Okay, so, intra molecular place an indictment on the same thing. All right, Awesome. So once again, we're gonna determine were to form immolates based on or if we should, based on if we could make a five or six members ring So Esther's air a little bit more simple because I don't have, like, possibilities on both sides. I only have really won. Would that really make sense? Would that give me ah, five or six member ID ring if it attacked the other Esther like this? Let's see. One, 23450 that's perfect. Six members rang. We know that's gonna be favored. Okay, So what I'm gonna do is draw the rest of the mechanism, which would be oh, facing up. Okay. And once again, since I was six member ring, I'm gonna draw my six my six numbers. I'm going to start at this corner, and I'm gonna move my way around counterclockwise. And guys, Really, you can start wherever you want, but that's just the way that I like to do it. Okay, so now I'm wondering what's missing in the different places, and let's even just do the whole mechanism. So at this point of the mechanism, what's missing? Well, it looks like one is missing. And Esther. So let's add, that one is missing this whole Esther thing. What else? Six is missing Two things, right? Six is missing and o negative. And it's missing an o 80. Perfect. So now that looks like it's correctly drawn. I'm gonna race the numbers because we know we did it right. So, guys, do you know what the next step of this mechanism is? What's the next step? The next step is that I have to kick out the leaving group so I would reform the key tone and kick out the E t. And what that's going to give me is a compound that now looks like this l e t and oops. Yeah, and then ketone. Okay, So what I'm wondering is, guys, did I get the right compound? Because remember that whenever you gotta Dykman a Dyckman should always yield. Ah, cyclic beta Keto. Ester. So is this a cyclic compounds? Yes. Is it a beta Keto? Ester? Well, I still have a nester, and I still have a key to one of the beta. So yes, this is correct. Cool. Right. So intra molecular got to get used to it in this chapter. Okay? This isn't the last time it's gonna come up. It's gonna come up again. I'm warning you, so get good at it now. All right, so let's move on to the next topic.
Consider the following reaction. Provide a stepwise mechanism to explain the given transformation.