Skip to main content
Pearson+ LogoPearson+ Logo
Start typing, then use the up and down arrows to select an option from the list.

Organic Chemistry

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

21. Enolate Chemistry:Reactions at the Alpha-Carbon

Overview of Alpha-Alkylations and Acylations



Play a video:
Was this helpful?
Hey, guys, in this video, I want to give you guys an overview of three separate reactions that all do the same thing. What they do is that they calculate the Alfa Carbon of a carbon eel, So let's get started. So, guys, adding our groups to Alfa carbons turns out to be very important synthetically. There's a lot of reasons that we would want to add our group to an Alfa Carbon, and it turns out that if we want to do that, we're not limited by techniques. There's actually three different things. Three different reactions that all do this. Okay, so we just write down the number three. Now, I'm gonna go through these three synthetic pathways now, all in order that you guys can get an idea of how they all work together. But your textbook might not teach them all in this order. I personally think that's a mistake. I think your authors made a mistake if they didn't teach them back to back because they all do the same thing. But right now I'm just going to give you this overview, and then we'll just take every reaction as it comes in your textbook every chapter that it's in. Then I'll do that reaction. But just keep this in mind that they're all really doing the same thing. So the first method is direct in a late calculation. Okay, So finally, Calculation just says that I'm going to use a base to form an anally, and that really is then going to attack and alcohol. Hey, Light. Okay, so then I would do like a backside attack, and I'm gonna get in our group on that Italy. Now, of course, we'll talk more about this in the actual page about Emily appellation. Okay, now, one thing to keep in mind is that pretty much any time that I tell you that you can calculate something, it means that you can also Aysal eight something now to a slate, something that means that you would be using an acid chloride. Okay. And the mechanism would be extremely similar, right? It would just be that your negative attacks the carbon and eventually you kick out the CL, so it means that you get a carbon Neil there instead of just in our group. Okay, but this is the first reaction that does Alfa carbon calculations, and it's called inlay calculation. It's definitely the most straightforward of the three. The second one is called Enemy in Calculation or Inamine Calculation. So you guys should be, you know, should be approaching the point where you learn about any means and how to make any any means any means our when we add a secondary amine toe a carbon eel in an acid catalyzed environment. Okay. And what an enemy in does is it makes I'm We're gonna go through this, of course, separately. But it makes a molecule that looks like this. We have a double bond, an end with to our groups. Okay, well, it turns out guys that any means are also great nuclear files at the Alfa Carbon. So any means can also do backside attacks on alcohol slides. And they can also add our groups. Now, you might be wondering what happens to the nitrogen. It gets hydrolyzed. Don't worry. There's a whole added work up, and you get rid of it. But we'll talk about it. But in the meantime, just know that it does the same thing in the same way. You could also react with an acid chloride, right? So, in acid chloride would just do an enemy in isolation. That was the second way. Now, obviously, it's more steps you can see. It's three steps. But the reason that it's so many steps is because the first step is to make the enemy and then the last step is to hide, relies the enemy. And then the middle step is the actual Electra follow we react with. So really, this is very similar to enemy. I'm sorry to Eataly calculation. It's just that you have to do that first step in that second step. Finally, we get to the last one, which is Ah, Cito Acidic. Esther, Um, and die carbon Neil Esther Um, calculations. Okay, so with Di Carbonell, Esther alcohol ations. What we do is we end up forming in an easily between the carbon heels because we know that that is the most stable place for an innovative form because it has the most resonant structures. That's the most acidic proton. That negative charge ends up doing an S and to attack and adding in our group in that location. Now we go through a complicated process where then we hydrolyzed the Esther and Dick are box elated Thio remove that entire species. And then we're left with the same exact thing that we started off with the other two reactions, which is just an Alfa alc. Elated. Um, Carbonell. Okay, so this one obviously looks like it's the most complicated, because now we have four re agents. But really, guys, it's a synthetic pathway that once you learn it, you're gonna get so good at it. It's not gonna matter. You're gonna be like pros at this. Okay? So, again, these three reactions I might not teach them to you in perfect order from here on out. Um, and that's gonna be because I'm going to try and follow your textbook as closely as I can. So sometimes your textbook will split this up between two different chapters. Okay? And that means that I'm going to split up the explanations in two different chapters as well. But I want, you know, always refer back to this page so you can understand to yourself that these three reactions are related to each other, very much so that they do the same exact thing just in different ways. All right, so that being said, let's move on to the first reaction