So basically, Declan's are specific types of by cyclic molecules that conform chairs. And all they are is that they're composed of two cyclo hexane rings fused together by one bond. So if you think back at the terms of the types of by cyclic molecules that we studied, this would be what we called a normal Bice. I click, OK, and the reason we call this one normal is simply because it does not have a bridge. Remember that Normal just meant that there were two rings refused by one bond in the middle. All right, so what are the differences between these confirmations? Well, because the fact that the entire molecules made out of just cyclo hexane is put together, that means that each side conform its own conform er alright. And what that's done is it leads to two different types of ultimate conformers that we need to know about Declan's alright and the way that we determine the differences between both is by looking at the positions of the hydrogen in between the two rings. So we have is I'll show you right now we have Trans Declan, and we have sis. Declan. All right, so What's the difference here? Well, trans decline is like it sounds. What it means is that the hydrogen zones that are attached to both sides of those bridgehead Adams remember those. These atoms right here are called the bridgehead. Okay. Okay. Well, the hydrogen is that are attached to the bridgehead. Atoms are trans to each other. What that does is it gives us a confirmation where you basically have to cycle. Heck, Sainz fuse perfectly together, and you have one each of the top face, one each of the bottom face. All right, so this is what a Trans Declan would look like in a plane or structure. And also as a chair confirmation. Okay, not to get cyst. Ekland, Sis, Declan forms when we still have those bridgehead. Adams. But both of the h is go towards the same side of the same face of the rings. Okay, so we wind up getting is you still have to care confirmations, but they're connected in slightly different way. Where now one is is actually basically going to go down or up, depending on how you draw it. And then the hydrogen are gonna go face the same direction. Basically So what that means is we have two different arrangements. We could either have the H is facing different directions, or we can have them facing the same direction. Okay, Sis versus Trans. Declan, which of these do you think is going to be the more stable form of Declan? What do you guys think? And the answer is that it's gonna be Trans, Declan, Okay, because of the fact that we're gonna have a lot less Starik contortion interactions in the transposition. Think about it. In this case, what I have is I have two rings that are as far apart from each other as possible. Okay, I also have pretty much no torch inal interaction between this age and this age there, as far away from each other as they could possibly get. So that's a really good Declan. Now it's like it, Sis. Declan, Sis. Declan. What it has is that now these rings are kind of in each other's space. One is facing the same way as before, but now one is gonna be facing down. And what that means is that there's gonna be a little bit of interaction. Oops. Ah, little bit of interaction between these guys. Okay, on top of that, now we're going to get is a little bit of Tor Schimmel Strain between those h is Okay, So the cyst Declan is actually significantly less stable than the Trans duckling. Okay, now, what kind of questions, will you? Professor asked. I honestly don't know. Not all professors talk about Declan's. Not all professors actually care about Declan's at its own subject. Okay, But I have found over years of tutoring that some professors will want you guys to be able to draw these Declan's and to be able to say which one is more stable, which ones least stable.

just in case you professor wants you to know about it, just in case he wants to throw something, he or she wants to throw something crazy. Let's just go ahead and, um, and do this one. All right, So what we've got here is a Declan and noticed that I've drawn the h is in a specific way. So pay attention to that, and it says, please draw the deck. Lynn as a chair. Confirmation in the most stable confirmation. Okay, so I know this is the first time you've done this, so I'm not gonna, like, ask. You have to pause the video and then come back because it's something that I don't expect You have to be able to do very well. Let's just do it together. And then you guys will see how this works. Okay, So first of all, which Declan should I be drawing? Should I be drawing Sister Trans? I should be drawing trans Declan. Why? Because I've been given a trans Declan. Okay, but let's say that I had instead given you another Declan that looks like this. And it just had sticks for ages. Okay, then which way should I draw it. Should I draw it since or should I draw Trans? And the answer is that I should still draw trans. Why? Because remember that Trans is going to be the most stable as possible, The most stable possible, Declan. So if it's asking me for the most stable confirmation, then I'm going to draw trans no matter what. Okay, so now we've got that settled. Let's go ahead and draw our Trans Declan, what that's gonna look like. And this is one of the hardest parts about it. Just be able to draw it. You draw your chair. Confirmation like normal. So I'm gonna do this. I'm gonna do that. Okay, then what you do is you draw another chair coming directly off of that one. Okay, so I'm gonna draw another stick coming off like that, and then I'm just gonna make the dip on the other side. So I'm gonna do this and this and that. Okay? And that actually came up pretty nice. I don't always draw it that nice, Okay? It takes a little bit of practice, but there we go. We've got our Trans Declan. Let's go ahead and we can draw on the h is just that they know what we're doing. And now all I have to do is have to figure out where to put that Beetle group. Okay, so first of all, how Maney carbons away? Is it from a bridgehead to Okay, the bridgehead is here. So what that means is that my terp util should be right here. Okay, so now it's asking for the most stable confirmation. Should I put it in the actual position or the equatorial position? Which one? Equatorial? Okay, so I'm gonna put this in the equatorial position and we are done. Okay, That is the answer to this question. That is the most stable confirmation of this Declan. Okay, now there are different variations of this question. For example, a professor could give you to substitue INTs. Then you have to figure out OK, which one wants the equatorial preference? Okay, but it would still be the same principle as we learned in share confirmations that you just go with the larger group wanting the equatorial preference. Okay, so I hope that that made sense. If you're Professor didn't talk too much about Declan's, then you can feel free to skip this or not practice it so much. Okay, But I just put this in here just in case. All right? So let's go ahead and move on.