21. Enolate Chemistry:Reactions at the Alpha-Carbon
Acetoacetic Ester Synthesis
21. Enolate Chemistry:Reactions at the Alpha-Carbon
Acetoacetic Ester Synthesis - Video Tutorials & Practice Problems
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concept
General Reactions
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Hey, guys. So in this video, I want to review the general reactions that ASIO acidic Esther's Congar Oh through. So, guys, this is like your cheat sheet for all the different reactions that you could do with a CDO acidic Esther synthesis. And the first step for all of these guys is always gonna be deep throat Nation formation of an equally right and that Italy is gonna selectively form right here because that's the easiest proton to pull off. Remember, it's the most acidic. Okay, so I'm just gonna go one by one down these reactions. So once you have your easily if you react that emulate within Al Kyohei lied, you're gonna get and calculation. Okay, guys. And that just makes sense. We've done that plenty. Okay, Now it turns out that usually you're gonna have to hydrogen on this on this middle. Carbon on this methylene carbon, usually most aceto acidic. Esther's start off with not just one hydrogen, but to Okay, So if you wanted to after you get the first calculation on, you could dip protein, ate the other one with another equivalent of base and then react with another. Al Kyohei lied so that way. By reacting twice, you would remove both of these hydrogen in, like, one after the other. And you would actually get now to our groups attached to the Alfa Carbon. So this would be die alg elation. Okay, now, just keep in mind to do a die alc elation. You need to react with the base twice in order to get both protons off. And it can't be two columns of base at the same time. It needs to be based, then alcohol. Hey, lied, then base again, then alcohol. Hey, Light again. Okay, Perfect. And then finally, the last two steps I'm skipping in all of these. So just you guys know I'm always assuming that at the end of this reaction, I'm gonna do what? Two reactions? Okay, I'm always assuming that I'm gonna do, plus h +30 plus and plus heat. Why am I assuming that? Why did I not draw it? Well, guys, I mean, I guess I could have drawn it, but it happens every single time. So it's a waste of space when I'm trying to show you is the stuff that changes the stuff that stays the same that that you always hydrolyzed and you always dick our box late. That's gonna hold true for all of these. Okay, so next what if you use instead of using, Um Ah. Hey, Light or an alcoholic? What if you use a terminal alcohol diet? Hey, lied. Okay, well, then, what you can do is you can actually cyclo Alcon eight. No alcohol A I'm sorry. Alka leads. Okay, you can cyclo Alka late because what you can do is you can react with your base, react with one side of your alcohol. Hey, lied. Then react another equivalent of base, then wrecked the other side of your alcohol. Hey, lied. That's gonna form a ring around the Alfa Carbon. And you're gonna get a ring with a size of n plus one where N is equal to the number of carbons in between in your chain. Okay, so if you reacted with a three carbon die Hey, lied. You're gonna get a four carbon chain. Why? Because these are the three carbons. One, 23 And this is the Alfa Carbon that you started with. So it's a four member ring. But only three of those new carbons came from the diet. He lied. And finally, guys, this one's easy a solution. So you know that you could attack here, kick out the C l and you would get a social group after you do your you know, your age throw plus and your heat. So, guys, I know this is a lot to, like, Go over. The only way you're gonna learn is just to, like, start applying it. So let's do this practice problem. I noticed it's five steps. So you're going to figure out what's going on? So try to do this five step mechanism. I mean, this five step product. Don't worry about mechanisms. Just worry about the product, and then I'll help out. Okay, By the way, I don't want anyone to get stuck on molecule to, so I'm gonna give it to you. Okay. Notice that it says B r ch two ch 220 What is that? So, guys, that's an ether. Let me draw it for you. That would look like this. Oh, in the middle, with these two groups coming off of both sides, so it be ch two ch two br ch two ch two br Okay. Excellent. So now you have no excuse to get this wrong because I'm actually giving it to you. Okay? So go ahead and try to do it yourself, and then I'll step in and show you how it's done.
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Predict the products
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Video transcript
Alright, guys, let's start off by drawing this Esther out because I hate working with condensed formulas, so let's just not hopeful. So I'm going to draw this out like this. My key tone Stage two C o r. So it's gonna be 00 e t. So that is a Cito acidic Esther. Okay, Now, the first free agent I'm reacting with is O C two h five. Is this a good base to use to informant easily on this die carbon? Neil, what do you think? Okay, guys. So remember that we said that you want to make sure that you're our group is the same between your Esther and your oxide, or you're going to get what, a transit stare? Ification. Right. So, is this a good choice? Yes, it is. Guys, Ethel and C two h five are the same thing. It's just different ways of writing it. Sorry, that was a little tricky, right? So it's fine. This is a good base to use this exactly what I want to use. So my first reaction is going to be that the oh grabs one of the h is and forms and in late here. Okay, now that easily. Let me see if I could do this down a little bit. I can't. So this easily is now going to react with my alcohol. Hey, lied. And my alcohol. Hey, lied. Looks like this. So again, it's br Oh, b are. Okay, so this easily is gonna do a backside attack. Let's not really backside attack. Let's do a backside on one of the bro means, and it's going to give me this. Move it up a little bit, so it's gonna give me Carbonell carbon L o A t. Plus, I've got this huge chain attached, so that's gonna be 012 b are. Okay, so now that whole thing is attached. Okay, Now look at my third re agent. Usually we would be thinking, Okay, let's tick our box late. I mean, let's hydrolyzed IndyCar Boxley. But no, I'm reacting with a second equivalent of face. What's that going to do? Well, guys, I've got one more proton there that can react, so I'm gonna take my base, and I'm gonna make an in late there. Okay? Now what's gonna happen? Guys that anally conduced another backside attack. Okay, so what we're gonna get is now a compound that looks like this with now. What does it have? Well, it has. It's a ring, right? It's gonna be a ring of what size? Well, to count out the size of a ring, I always start from nuclear file to electrify. Also, I would say guys that's gonna make a six member ID ring coming off of the middle like this were you guys just have to tell me if I'm missing anything. So this is 123456 Are there any atoms I should change? Anything I should add. Should I add a br? Okay, so I heard loud and clear. I need to change the four to an oxygen. Right. So let's do that. You'd be surprised how much I can hear over the Interwebs. Okay, well, see how the br guys the beer is just a leaving group, so I'm just gonna put plus b r negative. I don't need that. Okay. Excellent. So what's next? Guy that says now we're gonna use water and acid. What's that going to do? That's gonna do? Ah. Hydraulic distraction on my Esther that's going to give me this carb oxalic acid instead of Esther. Okay, so that's what my age three or plus does. And then heat. What is he going to do, Guys? He is gonna de car Boxley. Meaning that I take that entire car. Looks like acid off. Okay, if you're curious about the mechanism for that, definitely search D card box elation and what you're gonna get is that now that whole thing is gone. So that means the sick from a ring is just coming straight off of this Alfa Carbon. And that's it. It's gonna be that plus co two. And that's going to give us our final answer. So once again. So this was actually what This was a cyclo calculation reaction. Because I reacted with a die. Hey, lied And two equivalents of face and I was able to get a ring quote, right. Awesome, guys. So let's move on to the next set of videos.
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Problem
Problem
Provide the major product for the following reaction