Organic Chemistry

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13. Alcohols and Carbonyl Compounds

Nucleophilic Addition


Nucleophilic Addition

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Now I want to introduce a new mechanism that's gonna be really important for this chapter. This mechanism is really completely unique. You haven't seen anything like it in this course so far. And the name of it is nuclear Filic Edition. So what is nuclear Filic Edition? We'll nuclear Filic edition is actually one of the most important ways that carbonell compounds can participate in organic reactions. Okay, And how does this work? Well, basically, if you look at a typical carbon eel, well, you always have is you have a carbon attached to an oxygen and two groups on both sides. This is always going to produce a very predictable partial charge. And that partial charge you should be looking for is a partial positive notice that if I were to assign a positive and a negative charge to this molecule, I would say that the O is gonna have my negative charge and the carbon is gonna have my positive. Okay, Nuclear filic addition is gonna be the addition of nuclear files or negatively charged species to that Electra Philip Carbon. Okay, so the reason this thing is so reactive and the reason that carbon knows they're so good at this is because the carbon or carbon is Elektra Filic. Okay. And Electra Filic means that it's going to react with negatively charged things very, very well, that makes sense so far. So let's go ahead and look at the general mechanism for nuclear Filic edition so it can get a better idea of what's gonna happen. So nuclear filic addition in general involves a carbon eel. It could really be any Carbonell compound and a nuclear file that has a negative charge. Okay, um, it doesn't always have to have a negative, but most of the time it will. Sometimes it may be neutral just with a lone pair. As long as it has the ability to donate electrons, It could be a nuclear file. So when I first step, we were to try to predict the first arrow here. Where do you think we would start the arrow from? Would you start from the Carbonell? We start from the nuclear file. You guys remember these rules for mechanisms? Pretty sure you guys remember that you always start from the area of high density to the area of low density meaning that your electron flow is going to start from your nuclear file to somewhere, Okay? Because that's the thing with the most electrons. Now, where we're gonna go are gonna wanna go to a partial negative. Hell, no. We want to go to the partial. Positive. So we're gonna go ahead. And that arrow didn't work out. Let's try that again. We're gonna go ahead and attack the bottom carbon theological Philip Carbon. Okay, that makes sense. Because now have a negative and a positive interacting. Okay, But we've got a problem. Does carbon like to have five bonds? Remember that each mechanism arrow represents a new bond that's gonna be created? No. So if we make a bond, we have to break upon. Can you think of the easiest bond to break here? It wouldn't be to kick out one of those are groups. Okay, notice that right now I'm doing with a key tone. This could be these. There are groups, but it could also be an h like Aldo High. Regardless, Do we have something that's easy? Toe kick out? No. Our groups hate to be broken, often get a negative charge their terrible leaving groups. So this is the bond that we're gonna break. We're gonna break the double bond to the O, making a negatively charged species with a nuclear file on it. Okay, Now, this intermediate is gonna be very important throughout the course of this topic, because you have to pass through this stage every single time. This is called a tetra. He'd RL intermediate. Okay? And there's actually another me We're going to see a lot in or go to okay, in order to We're gonna deal a lot with this mechanism. But for right now, you don't have to know. It's super in depth. You just need to know the basics. Okay, so you've got this negative charge. What do you think we can do after that? Well, your final product that never wants to have a formal charge on it. So our last step here is gonna be two protein eight. Okay, so I'm gonna go ahead. I'm going to use some kind of acid. There always will be some kind of protein ating agent that you can extract a proton from. Okay, so now I've got my proton. What do I get it? The end. Well, what I have is I still have this nuclear file. But now I have in alcohol. Okay, So nuclear filic addition produces what we call substituted alcohol. Why? Because there's an alcohol in the final product and you have one extra substitue int afterwards. Okay, Sometimes that's gonna be in our group, but it really depends on whatever your nuclear file was. Whatever your nuclear follows that's gonna be with attached makes sense So far. Cool. So now what I wanna do is I want to show you guys some general, you know, the general mechanism. Now, this is the mechanism that we're gonna follow pretty much throughout all the topics that include Nuclear Filic Edition. But now I want to show you guys some specific additions that proceed through this mechanism. So let's talk about this one. What if my nuclear file is h minus hydride? Okay. What would you expect? Well, we would expect Is that your H minus? I'm just gonna draw this mechanism and then the other ones that won't draw the H minus attacks here kicks this up. Okay, What I wind up getting is an O negative. That pro Neitz and I wound up getting an extra h at the bottom right would you guys agree that this h here is the same as this h here? Cool. So what did we just do? What we just did was we added, Ah, hydrogen on one side and a hydrogen on another. Okay, now, you might have learned this already. You might have not. But just you guys know any time that we're adding to hydrogen across the whole bond, that reaction is called a reduction. Okay, so just us know if you've already learned about reduction, then you know this is the mechanism that reduction proceeds with Okay, if you don't know about it, that's fine. Just know that reduction is the name of a reaction that adds to hydrogen is across the double bond. Alright, So either way, it's cool that we could do a reduction through nuclear Filic edition makes sense so far. What if we use other nuclear falls, though? How if it's not h minus? Well, this is just a random one. What about CN minus? Well, you can imagine that CN minus same thing. We're gonna wind up attacking my carbon eel, and I'm gonna wind up getting a c n here. Okay, So once again substituted alcohol. Why? Because now I have an alcohol with one extra substitution on it. This would be a scion. Oh, group. Cool. Let's try another one. What about if you used this nuclear file? Okay, Now, I know that looks a little complicated, but you should know this nuclear file by now. Okay? There's a nuclear fall called an Alka night. Okay, if it doesn't ring a bell by now, you probably haven't been doing enough homework, Okay? Because you're probably going to see an alkali come up one you know, by now, at this point of the game, okay, And Alcon I'd is a strong nuclear file. It's also a strong base. You'd get the same thing. What you would wind up getting is a negative charge. Attacking, kicking up the oh, and what you wind up getting is C triple bond ch. Okay, now you might be wondering, Johnny, why did you draw it at an angle? Okay, because some of you guys might remember that triple bonds were always drawn in a linear fashion. Okay, so I kind of cheated right here. Okay, But the reason they didn't draw it straight down because it's literally gonna go off the screen if I draw it straight down. Okay. But just there's no if this was my organic chemistry test, If I was writing it for my professor, I definitely would have aimed the triple bond facing down so that it would be in a linear fashion because sp hybridized 180 degrees yada, yada, yada. Okay, remember, that comes from chapter one or two. Okay, cool. So I just want to show you guys, um these air different nuclear Filic editions, okay? And by the way, this Alcon I'd also falls into another category of molecules called in organa metallic. Okay. And I'll explain what that means in a second. Why am I giving it such a big name? Because I have a carbon and have a lithium together. Okay, Lithium is a medal. Carbon is an organic compounds that's called inorganic metallic. And just you guys know later on, when we talk about forgetting metallics or if you already have talked about organo metallics, organo metallic also follow the same nuclear folk edition mechanism. So what's the point of this? I'm just trying to tell you guys there's a very important mechanism. It's also very easy mechanism, so there's no reason not to really understand it. Okay? And we're gonna be repeating this several times throughout the semester. Alright? So I hope that makes sense. Let's go ahead and move on to the next topic.