Monosaccharides - Alkylation

in this video, we're going to discuss an opposition reaction of mono sack rights called calculation. So guys, mono sack rides have the ability to react at the oposicion or the oxygen position in several different ways. And the simplest of these is simply called exhaustive calculation. And what exhaustive calculation forms is, it forms four ether groups or four ethers and in a set top. Okay, so we formed four ethers in a settle. Let me just show you right now, this is what the product looks like. You have these 40 R groups, and then this. So are it. Looks like it's an ether, But guys, it's actually attached to a carbon that's attached when other O r. Right. So whenever you have to O. R is attached to the same position, you don't call that a die either. You call it an accidental Okay. Now, the re agents for this reaction are very straightforward, and they actually just resemble Williamson ether synthesis. Okay, remember the general idea behind Williamson ether synthesis is you taken alcohol then in some kind of base, you d protein ate it, so I'm just gonna put b minus you D protein ate it, and then you react it with something like an alcohol. Hey, lied where it can do a backside attack and you get an OAP. Our group does that kind of It's off the screen, But does that ring a bell a little bit? Williamson, either. Synthesis. You're just turning the O. H in tow, a nuclear file and then attacking Inoculate. Hey, lied And guys, that's actually what we're doing here. That's one of the sets of re agents we can use. So there are several ways that your textbook shows that calculation is possible, but I'm going to show you guys the three most common ways which are just Rx in base. That's literally what I just showed you right now. Any type of base in the presence of alcohol. Hey, Lied will perform a Williamson ether synthesis or in the presence of a least a primary alcohol he like, if it's secondary or tertiary, won't work because s and two won't be powerful enough. Um, also another leaving group that's possible in base is something similar to a Sultanate, Esther. So remember that Sultanate esters were also good leaving groups, right? So if you have something attached to Sultanate Esther or Sulfates Group. That would work because it's another good leaving group that could be attacked and then lastly would be, ah, leaving group in silver oxide, which has a slightly different mechanism that I'm going to go over specifically. Okay, But regardless, what's the general mechanism? The general mechanism is that you take once again, let's work with our beta d Google PIRA knows, and we expose it to some kind of catalyst. It's usually based, but it could be silver oxide. So that's why I put just catalysts. And what that's gonna do is it's gonna turn those groups into good nuclear files, okay? And then it's gonna attack the our kickoff, the X and what we're gonna wind up getting is a fully calculated, fully calculated because every single oh has been calculated Banda de Google piranhas side. Now, why is this important? Well, guys, we're going to discuss this later, But any time you have our group coming off of the an American carbon, this turns from being called a pirate nose to a private piranha side or a ring aside. Whatever ring, it is far random side, regardless, oh, side tells us that we have some kind of our group coming off of the an America position. Okay. Sorry, guys. Ready for the mechanism? Quote. Let's do it in the next video.

So let's start off with the easier mechanism of the three, which is the base promoted mechanism. And guys, I am being strategic about my use of the word promoted here. I'm not saying based catalyzed, and that's because you may not necessarily get all of your O H negative back. Um, the Net Ionic equation should be the same, meaning that for every minus I have on one side, I'm gonna have a on minuses on this side as well. But it's just that instead of being an O. H minus, maybe it will be like the conjugal base of this thing. So that's why it's promoted. Because you're not necessarily catalog. You're not necessarily generating the base of the end. Okay, quote So deep Throat Nation. This part is easy. We can use pretty much any base. It doesn't have to be o H minus. I'm just using that as our standard base, but there's so many bases that could be used for this. It could be any h could be L D a. It could be NH tu minus Whatever. Just a strong source of and ions okay, a strong, negatively charged base and what that could do? Is it? Can Fully deep protein ate the entire molecule. So what I'm gonna wind up getting is a bunch of negative charges. Okay, Now, these might not all happen all at once. Maybe they happen one at a time and react one at a time, But it doesn't really matter. The most important thing is that this happens five times. Okay, I'm gonna put your times five. Cool. Now that I have these negative charges, they're able to do a backside attack. That's the whole point. They're able to do an S and two mechanism. Okay. Now, specifically, the Alka Waiting agent that I used here is actually on the similar to a softening Esther. It's a sulfate group. And the reason that this one's important is it's a little bit harder. It's a little bit harder to visualize the knock, your hey lied. And that's why I'm using because I want to show you guys. So what can happen is that even though you might not know which side to react with, you've got a carbon with three. Hydrogen is that has a good backside, right? And then instead of having an ex, usually you would see this ch three X right? We're used to thinking that X is a leaving group. But what about all this? Isn't this whole thing a really good leaving group? It is, because once you put the negative charge on it, it's gonna be resonant, stabilized. So that's exactly what happens. You basically just do a backside attack on one of the metal groups and kick the electrons out to the Oh, so let's just amazing, amazing leaving group. And by the way, you didn't have to pick that side. You could have also picked this side, and it would have been the same thing. So what that's gonna do is it's gonna put a ch three right here and then it's gonna give you plus O s 03 c h negative, right? Oh, my God, that's off the screen again. I'm sorry. So what I was trying to show you is that plus o s 03 ch 33 And that would be like my contract based now, but it doesn't have to stop there. It would happen over and over again, so it would be s and two times five. So it would keep happening and I would get ch three here Ch three here ch three here and sage through here. So would get a fully alc elated, uh, glucose Peyron piranha side. Because once again, it's called up Iran, um, side because I have an R group attached to the an America position. Cool. By the way, I could have just replaced. I used a kind of weird leaving group because I wanted you guys to get practice, but I could have just switched it with our ex. And it would have been the same thing. It just would have been instead of that weird leaving group, it would have been you grab the r and kick out the X, but the net result would have been absolutely the same. Okay, Cool. I hope that made sense. Now let's move on to the silver oxide mechanism.

So now let's try out the silver oxide mechanism. So guys, unlike the base catalyzed mechanism or promoted mechanism where you're making the nuclear file stronger by giving it a negative charge, it's actually kind of opposite with the silver oxide mechanism. We're not going to touch the alcohol. The alcohol is going to stay neutral. We're just going to make the leaving group such a great leaving group that it's gonna end up getting attacked. Okay, so how does this happen? Well, the way that silver oxide looks is, it's an oxygen. Let's just draw right here. It's an oxygen that's attached to two silver Adams. Okay, And there's a very there's a pretty strong dipole where the O is really negative. Okay, so the, uh oh is gonna have partial negative. And then these are gonna have partial positives. Okay, because the always more Electra negative than the silver that makes sense. Remember oxygen's way more on this side of the periodic table and silver is like in the middle section, so it's not very Electra negative. Cool. Well, it turns out that what can happen is that it's gonna make a partial bond to the X and it's going to basically make the X more negative because it's going to attach to it and some of that negative energy. Some of that negative character is gonna be donated to the X, And what that means is it's gonna make this are more positive. So if I were to maybe draw it out in a line where it makes more sense, it looked like this are with a partial bond toe X x with a partial bond toe. Oh, and then oh, with the to a GS. And the way the specific partial charges work is that this is a partial negative, which is making this partial negative because it's attaching to it, which is making the are more positive than usual. And by being super super positive, it's going to basically make the O. H more conducive to attacking that always gonna have more of a reason to attack, because that are is more positive than usual. And then it's just going to kick off the leaving group. So it's gonna happen at the end is that we're going to get an are here, whatever our it waas for the alcoholic, we'll get our and then all we have to do is just multiply that times four. Okay, so we would end up doing this four times, and getting are, are Are are OK now, guys, I actually doubt you're gonna be responsible for this mechanism. Most likely, you just need to be able to recognize the regents, which are silver oxide and, uh, silver oxide and inoculate Allied or a good leaving group. But I just wanted to throw this in there, just in case that you guys would understand a little bit better. How the silver oxide catalyze the reaction, the OC elation, reaction. Cool. Awesome, guys. So we're done with this problem. Let's go ahead and move on to the next video.