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, here we have these two molecules and one's drawn in the chair conformation and the other one's drawn in a newman conformation, okay? So, looking at both of these structures, what do you notice about them? Well, hopefully the one on the left you guys can realize that this is actually a six membered ring drawn as a Newman projection, okay? Because this right here. Notice that these two are connected through this little structure right here right, this indicates that there's a ring. So, off that ring we can count the number of carbons we have, so let's say here we said these two methyls were coming off of carbon 1 and 2, we could also show that these two methyls are coming off of carbons 1 and 2, then you can go around and start counting and we get to 6 carbons and same thing here. So, both of these structures are cyclohexanes, okay? this Newman on the left could be converted to a six membered ring like this or another chair, okay? And what you see if we did this is that the one on the left this Newman projection, both of these substituents that they have are methyls and same thing here, right? Methyl and methyl but notice that in our chair it may be a little bit easier to determine what their relationship is because we can see that they're both equatorial but one is facing up, one is facing down, so what that means is that this is trans. Now, the one on the left here we have a methyl facing up and another methyl facing up, so what that means is these two methyls are cis to each other, so if you want you guys could convert this to a chair to even a cyclohexane ring like this, but what you'll realize is that we don't need to do that because we know that both of these are dimethyl cyclohexanes, right? We determine that and we know that they're in the 1,2 position. The only difference is that one will be cis and the other one will be trans, so what does that mean? what is their relationship now? Well, what that means is very differing their arrangement in space but they have the same molecular formula, so we call that stereoisomers, okay? Constitutional isomers would be if they have the same molecular formula but they differed in their connectivity and we get through that they are not the same, right? Because we determine that one's cis and one's trans. Alright, so hopefully that makes sense and you guys have any questions just let me know.