Leaving Groups

at the beginning of this topic, I made some generalizations about nuclear files and about leaving groups. If you remember about leaving groups, what I said was that there's a lot of different types, but the most common is alcohol highlights, right? That's what we've been using this entire topic. Another generalization I made was with nuclear files when I said that just think that a negatively charged nuclear follows strong and a neutral one is weak. And I just said, Just just let's just say that for now, Okay? What I wanna do for this topic is go more in depth on leaving groups and nuclear files so that we can really understand, like all the different types instead of all the different types of strengths, instead of just making generalizations. Alright, So let's get started with the leaving groups first. Okay, As I said before, alcohol Hey, lights are the most common leaving groups of organic chemistry. So 90% of the time you're just going to see alcohol. Hey, leads! And that's what you've been dealing with them so much because they literally are so ubiquitous. Alright, they're everywhere, But it turns out that there's other types of leaving groups as well. Another really common one being sulfa me esters. Okay, now these don't show up as often as Al Kyohei Allied's, but they do show up a good amount. What a sulfa. Nay, Esther is It's a molecule with the general formula. S 03 are okay now. Typically, we wouldn't. And this is actually the way it looks. By the way, the Sultanate Esther general structure is that you have your chain and say, this is my chain here. Okay? And let's say that this is attached and it's gonna be an O within an essence, to those. And then in our now, typically, would we expect it to be a good leaving group. No, remember that. Oh, is not as Elektra negative as an ocular. Hey, Light. It's actually, you know, further this way. So we would expect that would not be a good leaving group in o negative would suck, but this molecule special because it can resonate so much. Okay. And I did talk about this earlier when we were talking about leaving groups that we could once I get a negative charge there, this would be able to resonate and make double bonds and distribute that negative charge everywhere. So softening Esther's turned out to be really, really good, leaving groups even better than alcohol highlights, in some cases because they have so much residents available. So it's going to stabilize the leaving group just like a conjugate base would be stabilized by the residents effect. Okay, remember that parallel that I drew between conjugal basis and leaving groups? It's the same thing. So it turns out that the cell phone Esther, you might just see it drawn as s 03 are, in which case you need to know what that is. Okay, you also might seeing it drawn o S O to our same thing. Okay, that's just the way it's actually drawn out. There's an O first. Okay, You need to be able to recognize that that's a leaving group. But on top of that, like you could see a special type of cell phone. Esther, it turns out, cell phone Esther is the general category, but there's actually three unique types of softening. Esther's okay, and those are tosel its missile. It's and trifle. It's okay now. The difference between those three actually just has to do with the our group. Okay, so everything else is the same. The s is the same. The those of the same everything. The only thing that changes is the identity of the our group. So let's go really quickly into that. Okay, If that our group is just a metal group, which is this middle situation that's gonna be called, um, easily or missile group or, um, easily, once as the negative charge and it's abbreviated m s. Okay, So if you see that you know to soften Esther, how would if it's a benzene ring with a metal group on it? If it's a benzene ring with a metal group that's gonna be called a tosel it and thats abbreviated ts and then if it's a C with three efs instead of three h is then that's called a trifle or try fleet if it has once as the negative charge. Okay, now I know you guys may be wondering When do I use like the word tosel when I use toss a late. The ending eight just means that there's a negative charge, and we're gonna that's common throughout lots of chemistry, we say, instead of like I don't know instead of instead of like, I don't know, there's a in or go to. We use it a lot more that naming system. It just means if you haven't ate at the end, it just means you have a negative anti on. All right, So anyway, the whole point here is I don't need you to memorize exactly each softening, Esther. Okay. I don't want you to be able to draw it if I if I give it to you. But what I do want you to be able to do is recognize that if you see these weird letters like O. T s or O O M s or whatever that you're gonna know Hey, that this is a self in estrous. So it's a really good leaving group. Okay, Now, I did notice one little error here. This should have been O. M s not o. T s. So I am gonna I'm going to change that. But anyway, you guys get the whole point that basically, if you see one of these things, consider it the same as an alcohol. Hey, light. Okay, so if there's an Rx, it's the same thing as an O en masse. Whatever. All right. So that's the first leaving group that I want to tell you guys about. It's important. Don't pay too much attention to it. Just treat it the same as you wouldn't alcohol. Hail it. All right, So if I see a secondary missile, it that's the same thing as a secondary iodine. Whatever. The next one that I want to talk about is water. So water is actually a pretty common leaving group that we're gonna use, um, in a little bit. We haven't used it yet, but the way that we do it, the way we get water is a leaving group is to protein eight alcohol with a strong acid. Okay, so what you'll notice here is I have alcohol. Is alcohol typically a good leaving group? No. Typically, it sucks because once I kick off that Oh, what I'm going to get is O H minus. And that's very unstable. That's actually a really strong base, so it's not a good leaving group. But if I can protein ate the alcohol first with a strong acid like, for example, sulfuric acid, which is a really common one that's used. Then it's gonna leave as water. Let me show you. So if the first step is let's say like you, let's use an easier one. Let's just use HCL. Okay? If my first step is to expose the alcohol to my strong acid, guess what's gonna happen? My alcohol is going to grab the H and it's gonna become protein ated once it's protein ated. It looks like this. Oh h two positive. That's not very happy the way it is because I was a formal charge now. So now guess what can happen in the next step. It can leave all on its own just like an alcohol. Hey, lied would in a mechanism and then what you're going to get is you're going to get let's say, a carbon cat ion If this was an S and one reaction or anyone plus water is water a good leaving group? Is it stable? Yeah, it's super stable because it's just neutral. Alright, so see that by protein ating my alcohol First I could turn it from a bad leaving group. It's actually a really good leaving group. So now you guys know overall general idea here alcohol highlights of the most important you're going to see them all the time. If you see a softening Esther, it's gonna be one of these weird letters. Don't worry about it too much. Just treated the same as an Al Kyohei. Lied. If you see water with a strong acid treated the same way as an al Kyohei light, the whole point is just that it leaves. That's the end goal. I don't want you guys to get mixed up by all this. All right? Thes air. Really? The three main ones that we see. We don't see a whole lot of others. So don't worry about anything else. Is a leaving group except these three categories? Yeah.