Acetylide

What I want to talk about now is a way that we can make triple bonds into strong nuclear files. Now that might sound weird because if you remember, triple bonds are hydrocarbons and usually hydrocarbons aren't really good new nuclear files or Electra files. They kind of just sit there. But it turns out that triple bonds are uniquely acidic because of a principle that we talked about way back when he talks about acid in based chemistry. And we can use that to our advantage to make them strong nuclear files and these air called al canines. So let's go ahead and talk about how we can do that. So basically, I remember that we talked about in the acid and base chapter. So if you didn't watch that chapter, it's fine. Just gonna remind you now that terminal al kinds, the all kinds that have one H at the end are uniquely acidic due to an effect called the hybridization effect. Now, when we talked about acids and bases, we talked about that there were basically five effects that made things more acidic. There was the element effect, inductive effects, resonance, salvation, and there was hybridization. I know this might be like bring back some bad memories for you guys. Or maybe you just completely have no clue what I'm talking about. But hybridization was one of the things that could make something more acidic. And here's unexamined of a terminal all kind right there. And let's just go through the go through the hybridization. Basically, what the principal said was that the more s character that Adam has, the more acidic it's gonna be. And notice that this carbon right here has what kind of hybridization it has. Sp hybridization. The reason it's SP is because remember that the way we figured out hybridization was you count up the number of groups or what we called bond sites, and that would tell you how what the hybridization is. So in this case, I would just have one bond over here. Ah, second bond over here. That's two to bond sites equals s p. All right, so we know what the hybridization is. S p then out of the entire hybrid orbital, what percentage of that is s? That's actually really easy to figure out because you just say how maney higher, adorable, other total to There's the s. And there's the P s would be 50% off that. Okay, Now, just you guys know that's pretty high s character because, for example, SP three, that's a hybridization you should be really familiar with. At this point. S P three has one s and three ps, so that one has a 25% s character, so that one's a lot less. So having 50% is really good. That must mean this is pretty acidic. And it turns out that it is back in acids and bases. I made you guys memorized that the PKK of a triple bond is 25 which is unusually low for ah, hydrocarbon. Like I said, hydrocarbons air. Really sucky ass is usually for this to be 25. That's not bad. All right, so how are we going to use this to our advantage? What? Turns out that if we can use a strong enough base, we can pull off this h and give a negative charge to the terminal. Al kind. Okay, so we're gonna use a strong base to deep protein, ate that age and usually the basis that we use are either any h. Okay, sodium hydride or N a N H four sodium Am I? And both of these were very strong, small bases that are gonna be able to pull that hydrogen off of the terminal. All kind. So I'm talking about that green hydrogen above me. Okay, so that's going to create a strong nuclear fault that we're gonna call a sodium Alcon. I'd okay. And what the sodium Alcon eye looks like it's just gonna be a negative charge on that triple bond. So if I were just to erase some of this stuff and show you what the acid based reaction would look like for this reaction, it would be that I have Let's say N a h right. Well, that's gonna associate right, that would associate into n a positive plus h negative. Okay, Now the H negative is what's going to react. That's the base is gonna react with age. So would pull off the H and donate those electrons to the triple bond giving the Triple one now a negative charge. All right,

So the interesting thing about this is that we can use thes Alcon eyes in what's called multi step synthesis. All right, Now, for some of you, you're gonna have to learn that in this chapter right here for others. We're going to talk about that more later, and that's fine. But just want to kind of introduce you to a least one of the reactions that Sodium Alkhanov's could do, and that is to react with a primary alcohol. Hey, Light. So I'm gonna just show you guys right here. This will be a worked example where we do this one together and actually will probably do the second one together as well. Just because I know this is new for a lot of you. So first of all, notice that what I have is a terminal alkaline, and I'm reacting that with any NH two. So what kind of reaction could I expect from a terminal all kind and a strong base? Well, what I could expect would be an acid based reaction, So this would just be acid base. This would be that my NH two negative is going to react with my strong even with my terminal al Kind and produce a negative charge on it. So if I wanted to draw that mechanism, it would just look like this Where I always start for my negative charge, I pull off the acidic age and I give those electrons to the triple Bond. So what that's gonna make now is a triple bond. That looks like this isn't that cool? So now we have a negatively charged triple bond, and this is my nuclear file that's called an Alka nayd. Okay, The reason we call it a sodium Alka night is because a lot of times the sodium well associate with it, it will be close by. All right, so now that we have that, we could either stop there and for some of you guys, your professor is just gonna ask you to stop there. That's gonna be it. But others of you, your professor is actually going to take this a step further and say, Okay, now that we have that sodium Alcon, I'd what can we react that with, since it's a good nuclear file and it turns out that we can use primary alcohol? Hey, lied as a good re agent for this. Why? Because there's this reaction called a substitution reaction and substitution reactions are basically done by a negatively charged nuclear file attacking an alcohol. Hey, lied. Okay, Now, if you haven't learned the substitution reaction yet, that's okay. You're gonna learn it soon. If you guys have learned it, then this should be easy for you. Okay. But regardless, I'm just going to show you right now. It would happen. Basically, the negative charge would go ahead and attack the carbon that's attached to the bro. Mean? And it's gonna kick out. That, bro means so what we call this? We call it the substitution reaction because the B R is going to be switched with the nuclear college. In this case, is that very big sodium Alcon? I'd Alright, So just, you know, for those of you that already have learned substitution, you could totally use my flow chart to figure this out. Okay, if you haven't gotten there yet, that's okay. But eventually, you could just use my flow chart to figure out that this would be an s n two reaction. Okay, because there's a primary Al Kyohei lied. So now let's go ahead and draw our final product, Our final product would be basically a triple bond. But now that drill bond is gonna have a new bond. So it's draw that new bond. I'm gonna draw in black because that's the That's the color that I used for that era that came down. That's the new bond, and that needs to be attached to a three carbon chain. So I'm gonna touch it like this. So now what I have is a triple bond, and I have a three carbon chain on the other end. All right, so that's the end of that first reaction. Pretty cool, right? So we made our sodium Alcon eye, and then we did an S and two reaction and did a substitution on that alcohol, okay?

So now what I wanna do is I want to move on to one more question, and we're gonna do this one together again, and you guys are gonna try to help me out a little bit. Okay? So some of you guys have already learned most of you have already learned how to make triple bonds. Okay? And if you recall, the way that we make triple Bonds is by doing a double elimination off of diet. Hey, lights. Okay. Now, for some of you, this is gonna be new information. Meaning you haven't learned this yet, and that's okay. You're going to get to it. I'm just gonna show you how to do this here because this happens to you. One of the crucial steps off making an Alka night. In fact, usually what we do is you go from a single bond, then we make a triple bond. And then once you have the triple bond, we can make the balcony with Deep Throat Nation. I'm gonna show you how to do all that right here. Okay, so here, notice that we have a die. Hey, light. Right. Okay, So we have our diet. He lied and I'm reacting it with, actually three equivalent of a strong base. Why would I use three? That's a very strange number. And it turns out that two of those equivalents are going to be used to make the triple bond through double elimination. And then one of those equivalents is gonna be used to actually make the Falcon nine. Let me show you how that works. So basically, we have hydrogen. Here we have ah, hydrogen here. Okay. The red hydrogen can eliminate with the red br. The blue hydrogen can eliminate with the blue br. Okay, So what that means is that my first equivalent of NH two negative is going to pull off one of the hydrogen and make a double bond. That looks like this. Is that cool so far? Okay. And I still have, um Well, I should have drawn the age. Probably going up over here. Okay, That's the blue age. I still have the blue age left, okay? And I still have the blue br left. Okay, so that was my first equivalents. That was times one. Okay, Now, what about my second equivalent? Well, my second equivalent, this will be times too, can pull off the other H. So I'm going to do a double elimination. I'm gonna make my triple bond. And what that's gonna give me is look a triple bomb. So one. Okay, so now I have a triple bond from the first two equivalents of my base. Okay, But now I have this third equivalent. What's the third equivalent going to do? Well, if I add my third equivalents, this is times three. What that's going to do is it already has a triple bond. This is the sodium Alcon eye part. And this is the part that all of you guys should know. Basically, what we're gonna do is we're gonna take the acidic age and we're going to do an acid base reaction with its. We're gonna take that off and make a negative charge. And what I'm gonna end up with now is a sodium Alcon. I've Okay, this is really the only pathway inorganic one to make sodium Alcon eyes. We do a double elimination, and then we deep protein eight, and then we make our sodium Alcon. I Now I want to just point out that your professor doesn't always have to write times three. Okay. In fact, what they might write instead is they might right. Excess. Okay, If they write one of these strong bases either NH or any NH two in excess, that's really the same thing as this. Them saying times three, they're just saying reacted as far as it will go. So that just means reacted all the way to the sodium Alcon eye. All right, so now that we're at the sodium Alcon, I I'm reacting that with a molecule called C H three I What the heck is that? Well, if you think about it, that is an alcohol. Hey, lie. Okay, So I just showed you guys in the previous example how to take a nuclear file. Reacted with an alcohol. Hey, life and get a substitution reaction. So now I'm actually going to stop the video and let you guys try to figure out what the final product looks like. And then when you get out when you're done, I'll go ahead and show you what it iss All right, So get started on that

Alright, guys. So I want you to predict and draw the mechanism for this second reaction and we know this is gonna be an s and two. Right? So your negative charge would attack the backside to a backside attack onto the carbon with leaving group, right? And now we've got a problem. Because Carbon already had four bonds. That new bond is gonna make five bonds. It doesn't wanna have five. So if we make that bond, we have to break a bond and kick out the leaving group. And what is that going to give us? Well, we're going to get the same carbon backbone is before. But now there's one difference. Guys noticed that before I had a certain number of carbons, I actually had eight carbons. And I can count them out for you if you want. There's six in the ring, right? Seven and eight. So there were eight carbons in my structure before, and now after I react with saved three, what do I get an additional carbon on my structure? So now I start off with a I now end up with nine carbons, plus my eye negative ion, I don't care about that. Okay, now we're done. But what's interesting about this, guys, is that this shows that Alcon eyes are really good for what we call organic synthesis. One of the most important jobs of inorganic chemist is to take smaller, easy to attain molecules and make them bigger, in fact, that some people's entire job, their whole life is to take small molecules and turn them into molecules that they can sell for billions of dollars as pharmaceuticals. Right? So what we just did was we took a smaller molecule, and by using an Alka night, we made it bigger. So this is gonna be one of the main ways that we haven't or go one to make smaller molecules bigger. So it's something that you wanna look out for in the future. And you wanna hold onto that thought because we're gonna be using it more now, One other point before we stop before we turn the page. Always count your carbons. Guys, when you do these reactions, when you're adding them together to make sure you drew them, right? So notice that we start off with eight here and one here because my ch three I had one So that means that you really just adding them together. You should literally do this math at your exam. Eight plus one equals nine. I'm good. I drew it right. You'd be shocked how many of your classmates were going to get these questions wrong? Because they forget to draw one of the carbons in the end structure. Alright, guys. So let's keep going. Turn into the next page.