So here's what I hope will be a helpful cheat sheet for you guys to compare the different types of alcohols you could start with and stereo chemistry that you'll get it the end. All of these reactions, remember, are going to convert. Alcohol's too good leaving groups, but they are going to proceed with different stereo chemistry. So because this section has so much to do a stereo chemistry. That's why I made this entire access all about just stereo camp. All right, so let's go ahead and start off with what? If we want a good leaving group, we want to convert. I'll call to a good leaving group and you want the end product to be receiving. Okay, Well, if that's the case, then we could start with a secondary or tertiary alcohol, and we could use h X in an S N one reaction. Okay, H X is the Onley reaction in s and one that gives us to an anti MERS that gives us a combination of products. Okay, now you might be wondering Well, Johnny, why is it great out here? Why can't I also use that on a primary alcohol? Okay, we'll remember because primary alcohols don't form good Carvel cat ions. And in order to make a race emmick mixture, you need the Carvel cat ion. So I'm just gonna right here. Can't make Carl cada. And if you can't make the car will cat ion, that means you're going to do an s n two mechanism. Not in Essen one. So that's why it's great out. Okay, now, one more thing. I just wanna add Remember that what happens in the case of HCL, Can I also just use HCL by itself? No. Remember we use or the Lucas re agent hcl over zinc and two coins. The Lewis acid catalyst. Okay, cool. So let's keep going. What if I'm starting with alcohol and I want to get inversion of configuration at the end? I don't really care what the leaving group is as long as it's inverted. Okay, well, if it's primary alcohol, then I can use h x or SL Co two and PBR three. So just you know, s l C 02 and PBR three are always good options for inversion. Okay, Because the fact that you get a backside attack every time, why did I Onley put the h x s and to hear why did I not put it in the secondary position? Because if you guys remember H x Well, actually, if you do it with a secondary, it's actually gonna wind up giving you a sn one reaction. So that's why we can't use it in the secondary position. Weaken Onley. Use it in the primary position. If you have a primary alcohol Hey, lied. You will get a s and two, you will get inversion. But if it's secondary, remember, you make your carb okada and again and you would form or a scenic mixture. Okay, you might be wondering. Well, Johnny, why is this great out? Why can't I just do an inversion of configuration on a tertiary is Well, why can't I use s o c. 02? Because, remember, you can't do a backside attack on a tertiary. It's too crowded. Okay, so I'm just gonna put here bad backside. Since it's a bad back side, I could never do an inversion of configuration on a tertiary. Cool. All right, so lastly, what if I want retention of configuration? I don't really care what the leading group is as long as it's good. And I don't want to be alcohol obviously. Well, anytime you want retention of configuration, you're gonna use yourself. It'll chlorides to turn your alcohol into a Sultani, Esther. Okay, this one's really easy because it doesn't matter what degree your alcohol is. It always works. Primary, secondary, tertiary. It's always the same thing you're gonna wind up getting, Ah, Sultanate, Esther. And it's that easy. And then later on, you can react it. Okay, so hopefully that helps you guys to kind of organize the different ways that we can convert alcohol too. Good leaving groups. Professors love to test on stereo chemistry here. And that's why I would really emphasize knowing the differences in stereo chemistry between these options. All right, so I hope that made sense to you guys. Let's go ahead and move on.