EAS:Friedel-Crafts Acylation Mechanism

Let's take a look at the exact mechanism of Friedel crafts isolation. So Friedel crafts insulation is gonna involve in a seal. Hey, lied. Typically acid chloride complex ing with a lewis acid catalyst to produce an electro file. But in this case, my active Electra file is not gonna be a carbon cat ion like calculation. It's going to be in a see Liam Ion. Okay, now what does it a see? Liam Ion Look like it looks like this. You've got a carbon with a double bond to Oh, and in our group with a positive charge. Okay, so that is in a Celia My on. Can you think of why that would be a good Electra file? Full, positive charge. Now it is resonant, stabilized. There's two different ways that it can be drawn. That's one way another way would take would be to take these electrons and move them into that carbon to become a triple bond. And the other way to represent it would be to now move the positive up to the O. Okay, so just you guys know these air both a asili. Um, ions. Obviously the hybrid is gonna be a blend of both of these. It's gonna look like, you know, some mixture of those contributing structures, but the one that's easiest for us to use that helps us to visualize the mechanism. The best is this first one, right, Because the first one shows the positive on the carbon. That's what we're gonna be attacking. So when I draw the asili, my and I'm going to draw the first resident structure. Awesome. So notice that what are we trying to get at the end? We're trying to make key tones. Okay, So or our end product will be a key tone on the benzene ring. Let's go ahead and take a look at this mechanism. Okay, guys, So really, there's nothing tricky about this mechanism. What we're gonna do is we are going to donate our chlorine to the Lewis acid catalyst and with that's going to give me is in a Celia my on. I'm going to get carbon. The 10 single bond are positive. Plus my a l c l four negative. Okay, So as you can imagine, this is a wonderful Electra file for my bending to react with, and it's gonna grab the carbon now something to keep in mind, guys, is that this is not Ah, carbon counting intermediate reaction. So that means we don't have to worry about shifts. So there's no rearrangements. Okay, you might say Well, why? You know, that's not how you spell. Let's try it again. Arrange ments. Okay, guys, the reason that it's not gonna rearrange is because this is a resonance stabilized Electra file. So it doesn't want to break resonance by moving to the our group. It just wants to stay where it is, because where it is, it can resonate. So you don't have to worry about that. So you don't have to worry about any of the complications of rearrangements, which is great. And we're gonna discuss mawr later. Why that's so important. So let's go ahead and draw this full mechanism. That's it. I'm just gonna make up on. So I have to break upon. No, I have a full cat. I in their empty orbital so I don't have to break upon it can accept that those electrons. Now I'm gonna draw my sigma complex, which would look like this now with C double bond O r. Positive. And you guys know what to dio. Move it over. Control your double bond. Draw my cat eye on here. Move it over again and I get my cat. I end up here. Okay? Now, actually, I mean, this is right, But always remember, you need to draw that hydrogen, right? The hydrogen is important because it's part of the elimination step. Right? So let's just draw the hydrogen facing up. What do you think we're gonna use? By the way? I didn't draw the hydrants and the other ones. It's not necessary. You can. You can just draw the hydrogen in the last one if you want, cause hydrogen can always be implied in a bond line structure. So what's gonna happen in this last step? Yeah. Guys, you just use your conjugal base, right? Your ales seal four a o. C l Oops. That's not what I meant. That's erase. Okay. C l a l c l three negative. And, as always, I'm just gonna grab the electrons from that bond and do my beta elimination. What that's going to give me is now a key tone. Plus, I'm going to get my Lewis acid catalyst. That's regenerated. Plus, I'm gonna get my acid as a byproduct. Okay, once again, guys know rearrangements are required are possible here. So there's less to think about your always just gonna get your key tone on the benzene ring. And that's it. Alright, so that's it for this mechanism. Let's move onto the next one.