21. Enolate Chemistry:Reactions at the Alpha-Carbon
Formation of Enolates
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So, guys, now we're gonna focus in on one of the most important intermediates for all of organic chemistry. And that's called the annihilate. Okay, So specifically in the base, catalyze Todd memorization mechanism. Right. The base catalyzed version, we form a resonant, stabilized intermediate called in Italy. Okay, let me show you. Remember that in the base catalyzed version, what winds up happening is that my own negative grabs the Alfa Proton right away. Right? So I wind up forming a double bond here and then kicking electrons up to the O. Okay, this gives me a possible resident structure. Though we're on the one hand, I have the negative charge on the, uh oh, but I could easily resonate that down to the carbon, right? Cool. And then it could resonate back up. Both of these air considered the anally anti on, and both of them are correct. But for the purposes of this section, one of these is gonna be far superior in helping us predict what a product will look like. Okay. And the one that we're gonna use is the one where the negative charge rests on the carbon. Why? Because that's gonna help us to realize that Alfa carbons in a basic solution are actually good nuclear files. Okay, that's totally different from anything else we've done with Carbon kneels before because up until this point, guys, we've been taking carbon eels, and we've been saying that they're good Electra files. Okay, that it's good to add stuff here. Okay, But now what I'm telling you is that the Alfa Carbon is actually a good nuclear file mean that the Alfa Carbon can actually do this crazy. Right? So we have a whole new set of reactions. Ah, whole new branch of carbon. Oh, chemistry opens up to us when we use immolates. Okay, so now what I want to do is I wanna use the next section to compare nuclear fill condition, which is a mechanism you should already be familiar with with what's with the mechanism of elites
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So by now, I really hope that you're familiar with nuclear Filic Edition because it's just that important. Remember that you've got a partially positive carbon on the carbon eel Nuclear files can attack it, kick electrons up to the O I wind up getting a tetra hydro intermediate. And remember that at this point, that O negative has no other choice other than to protein E because it has no good leaving groups that it can kick out. So just gonna protein eight instead and make a substituted alcohol. Okay, this is the reaction that green yards undergo. That reduction undergoes and lots of other negatively charged nuclear files. But what happens if instead of reacting my carbon deal with any random nuclear file? What if I reacted with a base? Okay, Was the base specifically suited to take off an Alfa Proton? Well, what's gonna happen, guys, is that you've got a h, right. If you use a base to pull off a proton, what you're gonna do is you're gonna make it easily, and I on Okay, this is a completely new reactive species because now if I have a negative charge on that carbon, I can use it to attack random Electra files. Okay. And if I can attack a luxury electricals with my Alfa Carbon, that means that I'm gonna have a way to put things on the Alfa Carbon, meaning that the products of these immolate mediated reactions is Alfa substituted carbon eels. We're actually get things on the Alfa Carbon, and that's super important. So, guys, nuclear Philip condition is what we're used to seeing with carbon eels. But the new mechanism that we're gonna be using in this section is called Electra Filic Alfa Substitution. Because the fact that, um, you're now attacking Electra files, not nuclear files, right? And you're not gonna be substituting things on the Alfa position. Notice that at the beginning I had in H and I ended up with an E. That's gonna be the whole theme of this area. When we deal with immolates, we're gonna be using them to substitute hydrogen for whatever Electra follows we want to react with. Okay, So awesome Hope that made sense that the general reaction. Now let's move on to some specific reactions
Additional resources for Enolate
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