Organic Chemistry

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18. Reactions of Aromatics:EAS and Beyond

Diazo Sequence Groups

We've learned about blocking groups before with sulfonic acid (SO3H), but now let's see how we can use a diazo group (N2) to function the same way. 



Sequence Groups

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Alright, guys. So now that we know about die as a replacement reactions, we have to take that into account when we think about sequence groups. So as you guys might recall sequence groups or groups that have the ability toe alter the sequence of an aromatic synthesis. And there are groups that can be easily transformed from one type of director to another. Okay, and we have examples of this in E. A s. But now we have diarrhea reactions as well. We have to take into account Now. Here's another definition. Guys blocking groups. What's a blocking group? Remember that a blocking group is a group that really Onley acts to direct the other reactions and then it's completely removed. So the only way that you would know that it was there is because you can see what it did, but not because it's actually there anymore. What turns out. But now, now that we know about H three people two or hypo phosphorus acid, that on group is used to block the pair position and force Ortho substitution. How? Because we know that we know that we can remove on die as a group with H Threepio too. So that means that we can use diesel compounds as blocking groups and then easily remove them after. Okay, so let's talk about something we already know. So Clements, introduction Clements introduction takes a meta director. And when you react zinc and mercury over HCL, you're going to get an O p. Director. Okay, so it's a sequence group because I just changed the direction of the directing effects of my substitution side chain oxidation. So I know that I can oxidize and our group using cam in all four and BCE and heat and acid, And it can oxidize it too. A Benz OIC acid, meaning that it started off as an O. P. Director, and it ends off as a meta director. Okay, we know that another directing effect or I'm sorry. Another sequence group would be reduction of am I and not nitro groups. Okay, so in this case, I'm doing a nitro, but Hamed's can reduce is Well, um, we learn more about that in your means chapter. Okay, so don't worry too much. But anyway, we know that reducing agents love to reduce nitro groups, so obviously we could use lithium aluminum hydride on and there's a few others that we've learned. You guys know my favorite. We could use the Stannis chloride, right? And that would reduce my nitro thio to an Anna lean. But now here we go. Here's the die as a reaction specifically. So for Dyas Oh, I could start off with Dyas. Oh, noticed that this is a meta director. Okay, because of the fact that there's a full positive charge. What type of director would that be? You have to met, right? Because it's a strong deactivate. Er okay. And after I change it out with the replacement reaction, I could make it into a donating group. So or Ortho pair director. So can you guys think of a substitution or I'm sorry, a day as a replacement reaction that could make a donating group instead of a withdrawing group. Can you think of one that would turn it into an Ortho Parra director? So just you guys know there's plenty that you could use, but one of the easiest would be how it just water. What would water do as an example? I'm just gonna put here e because it is just an example. Water would turn my dyas. Oh, into phenol. Right? And once it's final, what kind of director is that? Or so para cool. So you guys can see And there's a lot of other ones that we could choose that air Ortho pair directors. And then finally, we have die as a substitution with a proton. So you start off with Dyas. Oh, that's a meta director, but you could use it as a blocking group. So if you reacted with h three po to you're gonna wind up replacing it with H. And this is our blocking group. Because what you do is you block that site from reaction so you can react something else somewhere else and then take it off. All right, so these are things that we have to keep in mind when we do synthetic synthesis with, um with dyas. Oh, reactions. Okay, but to keep all of these sequence groups in mind All right, so let's move on to the next topic.