For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
Hey guys. So, for this question we're giving to Newman projections in this set we have four different methyls coming off on both of them, right? Now, let's look at their relationship, we have two coming off in the front here, two coming off in the back, here we have one coming off in the front and three coming off in the back, so what do you guys think, can we determine their relationship by this Newman? Well, not really. Looking at this Newman projection we can see that they have the same number of carbons but we need to determine what is their relationship, so the best way to do that is convert both of these into a bond line structure. Now, we can do that by first showing that there's going to be two methyls coming off that front carbon and then we're going to have that back carbon, right? That's going to be the back carbon and there's two methyls coming off of that, so we should be left with a structure like this. Now, I'll go ahead and try to do the next one. Noting that does the front one we're going to have just one carbon connected to the back. Now, coming off the back, we're going to have three carbons, okay? And you should end up with something like this. Now, we can actually get both of these a name because we can count the number of carbons that are in the longest chain and get to four and so here we can go 1,2 or if we want to go the other way, we can go 1, 2, 3 and 4, so what do you guys think? Well, both of these are butanes right? Now, notice that at two we have a substituent coming off and at three we have a substituent coming off. So, essentially this would be a 2,3 dimethyl butane. Now, let's move on to the other one. Now, here do you see any substituents coming off on 3? no, right? But you do see two methyls coming off on two, so notice that the one on the right is going to be some kind of 2,2 dimethyl butane but the one on the left is going to be a 2,3, so what does that mean? we know that both of these are going to have the same molecular formula, right? They're going to be both 6 carbons, so the only difference between them is actually their connectivity because notice that all they did is take one of these methyls and moved it over so that now we have a carbon that has three different, three other atoms attached to it, okay? Because carbon 2 notice is connected to three one and then it has those two substituents, so we can call these two constitutional isomers because the only difference is the way they're connected but they have the same molecular formula, so that's why they get the name constitutional isomers. Alright guys. So, as you can, we can recap and say that we have these two Newman projections but it's hard to determine their relationship so that's why we converted them to bond line and then try to name them or for this one we could actually just look at how our substituents are connected. Alright guys, so hopefully this makes sense.