Monosaccharides - Aldose-Ketose Rearrangement

on this page. I want to talk about another transformation that mono sacha rights can undergo in base. So guys in basic conditions, mono sacha rides will undergo a multitude of todd immunizations and isomerization. And this is one reason that we typically don't want to expose Monos Ackroyd's to base because you get such a mixture of ice summers that it just makes a big mess out of things. The most profound of these transformations, it's possible, is for the is the ability of all doses to reverse a ble rearrange into key. Tose is in the presence of base, literally making brand new mono sacha rides. This process is called a bunch of different things, so we have to keep our names straight. First of all, it's simply just called on Aldo's key toast rearrangement. So that's the title of this page. It's also called the End. I'll rearrangement so in denial is the intermediate that's going to be used for this process, and this is called the in denial rearrangement. If your professor says that they want you toe be able to draw the mechanism for the end, I'll rearrangement. This is the reaction they're talking about Finally, it's actually also called the Low Breed Day. Brilliant Van Eck and Stein Reaction. Yes, that's the real name. If you look on Wikipedia, that is a name for this reaction. So, guys, we've got to keep our names straight. But at the end of the date, that's really the hardest part is not gonna be a super hard mechanism. The name is worse than the actual mechanism. Okay, So, guys, before I show you the mechanism, I want to show you the general reaction So you guys can get a sense of how, uh, potentially inefficient this type of reaction is. So once again, we're gonna pick on beta d glucose. PIRA knows because this is a This is a mono sack ride. You should know very, very well by now. And what have we already discussed? We've already discussed that in base. It's possible for a beta an imer to mutual rotate toe, a combination of Alfa and beta animals that's called mutual rotation, right? We've also already discussed how it's possible in base for a mano Sacha rightto epa. Mariah's the sea to position. And that's what we get here in the second product, where glucose piranhas turns into a mana. Pira knows because the sea to position becomes Rasim ized, where now you have half of it going right and half of it going left, and that is called memorization. But finally, we also have the ability to completely rearrange glue cope. Ira nose into a Foreign knows that's made out of a key tone. So it's possible for the beta d glucose PIRA knows to become defrocked dough Farinos, which is just a completely different mono sacha ride a different ring. Everything's different about it. And this happens through what we call rearrangement or what's also, as we listen what's known as the in denial rearrangement. Okay, so what I'm gonna do in the next video is I'm going to show you guys the whole mechanism for how we obtain this molecule. All right, so let's go to the next video

So we already know that base is the ability to remove the alfa hydrogen of Amano sack ride. And that's actually the same exact step for the end. Iol rearrangement cause remember, the in denial rearrangement has to get to the end iol intermediate. So that means that the first few steps of this reaction are exactly like memorization. So my ohh comes in, grabs the alfa hydrogen forms. A double bond kicks electrons up to the O. What I wind up getting is a double bond with a negative charge where stereo chemical information has been lost from carbon too. And we know that to get to the end, I'll we're gonna have to protein eight. So let's go ahead and do that. We're gonna protein ate with the conjugate base of with the conjugate acid of water and that's going to give us our in diet, Okay. And then we know beyond that that if we then just go backwards throughout the whole mechanism that we just did and deep protein ate that age. We can go and f memorize, see to to get manos. Let's show how how that happens. Once again, you would then use o h minus and just pull that H right back off to form a negative charge here. Double bond. And then we would use water Thio protein, eighth e Alfa position because you reform the carbon, Neil, that on the double bond grabs the H and kicks off the O. H. And we wind up getting is de manos. So this whole process that we just did who is just EPA memorization, But it was memorization specifically through the M dial mechanism. Now, this isn't the only thing that you could do with an in denial, because what if the base, instead of grabbing the top proton What if it grabbed the second proton? What if it grabbed the proton off of carbon to would that change? The product actually would change it very significantly. So let's see what would happen if instead of grabbing the top one, re grab the bottom one. So if I grabbed the bottom one unformed, a negative charge, it's gonna need to arrows. Let's just do it. Certainly like O H minus. I grabbed the H and then the H gives its electrons to the O. What that's gonna form is a double bond. Here with the negative charge and an H and guys. This is an email late once again, but now it's the other equally. So now it's possible to just prote me, or it's possible to just basically get regenerate that double bond and get rid of it. So basically, what I could do is I could take my water on. I could use this negative charge here to make the double bond and protein eat the Alfa position. So basically everything that I did with this anally would happen with this one. But now it's happening with the double bond being reformed on C two instead of C one. Notice how on this until eight above for the EPA memorization, See one reform the carbon hell. But for my bottom in denial, C two formed a carbon hell. So what that's going to do is it's going to give me a double bond here now, an H just that's attached an extra age that's attached to here and this blue age is still oops, this blue age is still here. Okay, so what we just did is we just turned deep glucose, which is in Aldo Heche sauce into. We just turned it into a Keto hex O C D fructose, because we were able to use the dial rearrangement. Now I wanna point something else out to you guys. Now that we have the carbon, the carbon, you'll see. Two. Theoretically, now it's possible to even EPA memorize the C three position because now I could easily use base to pull off this age and do the whole system over again. In fact, I could even form a key toast through an in denial rearrangement I could form I could for mosquitoes here at the C three position and so on and so forth. But these types of crazy rearrangements Onley tend to happen in very strongly basic conditions. So usually we're not going to see EPA memorization or isomerization of the entire chain. Usually for professors just asking for an in denial rearrangement. They just want you to do it toe one carbon, not to do it to all the different carbon, because that could take forever. And that would require very, very basic conditions to make that favorable. Alright, so, guys, I hope this video helped. Now you understand how the end I'll intermediate is a very important Intermediate, not just for EP immunization, but also for what we call rearrangement. Because now we can get a key toe or a key tone from it. Awesome guys. So let's move on to the next video.