Axial vs Equatorial - Video Tutorials & Practice Problems

What is a chair conformation?

so far in most of chemistry, we were drawing rings like that, and we always assumed that they would just be plain or that they would just be like a flat thing on the paper. But it turns out that cyclo hexane actually exists in a puckered, puckered meaning that there's like some angles that air in different directions, puckered form to alleviate both torch inal and ring strain. Remember that torch it'll strain is the strain of having hydrogen eclipsing over each other. Okay, so imagine that if it was plain or it would have tons of torch, it'll strange because all of those ages would be perfectly overlapping. Okay? And the ones in the bottom two. It would also have a lot of ring strained because thes bond angles would be 120 degrees versus it wants to be at 109.5. So what winds up happening is that it winds up bending a little bit to form what we call a chair, okay? And the chair is almost like the perfect cycle of cane because it has pretty much no ring strain and no torch. It'll straight

How chairs flip from one conformation to another

So I want to go ahead and talk about these chairs. And it turns out that, like, single bond, remember that single bonds are allowed to rotate as much as they want. It turns out that cyclo hexane can flip okay, And it can flip to form two different what we call chair confirmations that air in equilibrium with each other. Okay, so these chairs basically have to do with bonds just bending back and forth, but it doesn't actually change the molecule. It's just a confirmation. Can't remember. Confirmations aren't items. They don't change the molecule. And the reason that they're kind of chairs is imagine that, like, you're just like sitting there, and you're like, this is like, your like, thrown and you're like, I don't know. You got, like, a bag of chips and you're watching TV. All right? This is like a man's paradise right here. Xbox. Alright, so that's gonna be my chair. All right? It doesn't look that comfortable, but you'd be surprised. It's actually pretty amazing. So this would be one of the chairs. The other chair would just mean that I'm sitting in the other direction. So now this guy over here he got, like, limited Edition, other type of chair and this guy's rocking it. He loves it. Okay, so this would be like a right facing chair, and this would be like, ah, left facing chair. And these chairs are in equilibrium with each other. Okay, so it's never just gonna be right. It's never just gonna be left. It's always gonna be passing through now, in order for it to flip from one to the other, it's gonna have to pass through this really unstable confirmation that's called the boat on the way you can think of it is kind of like I'm on a boat, all right, so I'm just, like, chilling and I am on a boat and I've got my brewskies and it's awesome. I'm swimming from Cuba. Alright, So anyway, that would be a boat. And it's not very stable. Alright, it's probably not gonna last too long. So and that's because of the flagpole interaction. That's what it's called flagpole interactions off these h is here that are basically around this guy's head and they're like, kind of like, really close to each other. Okay, so basically, the boat is a very minimal amount of the of the cycle. Heck, sane. Usually it's going to spend its time either being on the right chair or the left chair, okay?

How chairs flip from one conformation to another

So, in order to understand chair confirmations, we have to understand there's two different types of positions that chairs have. So I want to just go ahead and just draw these out. And hopefully this will make sense to you guys. The first and the easiest puts positions to visualize are what's called the axial positions. Okay, the actual positions are going to follow. Oops, that's not follow. Follow each corner. Okay, So what that means is that if your corner is facing up, then your actual position is gonna face straight up. OK? So you can see if this corner was kind of facing a little bit on the upside. Okay. What about this corner? What direction is that? One facing actually is facing kind of up because I have one that's going slightly up slightly up. So I would expect my actual position to go straight up from here. How about this one? That one? Both of them are going down, so I'd expect my actually go down. And if you draw in all your actual positions, they're gonna look like this. Okay? The actual positions are always the easiest ones to draw, and you should always start off drawing the actual positions. Okay. Are you guys cool it that so far they follow each corner. Now the equatorial ones are the tricky ones. And they're the ones that if you're like a dude and you can't draw these are the ones that are gonna mess you up on the test. All right, so you're gonna be extra careful just already. Know there's you have, like, multiple risk factors for getting this question wrong. If you're a guy and you can't draw, so you have to be extra careful, equatorial, and I'm just gonna say, right now I am one of those people. So absolutely, very careful. So equatorial is gonna be What I'm gonna say is it's gonna be slightly opposite to the direction of the axle of each axle. Okay, So what that means is imagine that each of the corners have to h is right. So some of the h is air gonna be on the actual positions. Each position has one axial each. Carbon has one axle each. Carbon also has one equatorial. The equatorial positions are gonna face slightly opposite to the axle. So that means noticed this one right here, that one is facing up, right? That actual. That means that my equatorial position should face slightly down. Okay, so that means this h the equatorial one would face slightly down. Now let's look at this one. This one is facing down. So that means that my equatorial positions should face slightly up. Is that cool? And we would do the same thing for all of these. So then this one, my equatorial position goat, would go slightly up. This one might equatorial position go slightly down and like that and like that. Okay, now you might be wondering why is it so important to draw these slightly down and slightly up? The reason is because I already made this huge point about how cyclo hexane has no ring strain. Right? Already kept telling you guys that no ring strain means that the bond angles must be around 109.5. Right? That means that you need all of these hydrogen to be 109.5 degrees away from each other. Okay, So, for example, if you draw your hydrogen, let's say you draw your hydrogen like this, okay? Is that right? No. Because if you look at that bond angle. That bond angle is gonna be much less than 190.5. That's gonna be wrong. Okay, so you need to make sure that you're always protecting that 19.5 bond angle in every single corner. On top of that, I'm not just being nitpicky. This is actually gonna be the difference between you getting the question right or wrong. Once you start getting consistent, trans consistent trans is based off of these bonds. Okay, These bond angles. So it's really, really important that you don't let yourself get lazy, and it's really important that you save yourself the headache and just start drawing them right from the very beginning, So that would be a much better h to draw. Okay, So now that you guys understand the two different types of positions, let's go ahead and go on to the next video