Skip to main content
Pearson+ LogoPearson+ Logo
Start typing, then use the up and down arrows to select an option from the list.

Organic Chemistry

Learn the toughest concepts covered in Organic Chemistry with step-by-step video tutorials and practice problems by world-class tutors.

27. Transition Metals

Eglinton Reaction

1
concept

Eglinton Reaction

clock
2m
Play a video:
Was this helpful?
in this video, we're gonna take a look at the clinton reaction. Now we're going to say that the clinton coupling reaction involves the coupling between two identical terminal all kinds with a copper catalyst and base. Now we want to make sure that the two all kinds we're using are identical so as to avoid a mixture of possible products. Now we're going to say here that the reaction uses a copper catalyst in the formation of a buy al Caneel product and like coupling reactions, it has the same two driving forces. One driving force is the formation of conjugated products. Remember the more conjugation our compound possesses than the more it is stable. And we're gonna say that another driving force is that the transition metal catalyst is trying to obey the 18 or 16 electron rule. Now, unlike other coupling reactions, it doesn't use a catalytic cycle and instead radicals. Now the general set up for Clinton coupling reaction is we have all kind one which is identical to all kind to. We utilize copper one and copper to catalyst. And we have peered in as our base. Remember, peer Gynt is like benzene except there's a nitrogen within it. And basically what happens here is that we have the loss of hydrogen from both of these so that the al kind portions that are left at the end combined together to give us our by al kamil product. Now we're gonna look at the mechanism later on to see how it really occurs. But for simplicity sake, you could just think of it as the two hydrogen um combining being lost and we're not necessarily combining but they're being lost. And then what's left combines together Now, since our two all kinds are identical, that means that there are groups would be the same. So here we're gonna say the R. one and R. two groups of the terminal. All kinds can be represented by um vinyl or real groups. They can also be represented by an owl kill group or even another al kamil group. So that's just the basic setup of the clinton reaction. Now that we've talked about the basic steps involved, click onto the next video and see how I approach the example question we're asked to find the final product.
2
example

Eglinton Reaction Example 1

clock
2m
Play a video:
Was this helpful?
although we haven't gone over the coupling mechanism for the clinton coupling reaction, we can take a simple approach to find our answer. So if we take a look at this example here, it says, determine the product from the following clinton coupling reaction. Now, here we have two identical terminal all kinds. If this were an actual question, you wouldn't have the number two here given to you, you'd have to realize that oh, I'm dealing with the clinton coupling reaction. Therefore, I'm dealing with two identical terminal al kinds. So it's kind of implied that there isn't just one of these all kinds. There's actually two of them. Now, all we have to do is we're gonna draw one terminal AL kind, then realize that there's gonna be an identical one also involved in the reaction. And in terms of simplicity, we know that through a process that we haven't seen yet that the hydrogen that are on the terminal al Qaeda carbons will be lost somehow, and that the AL kind carbons then would connect with one another. This would give me my final product as okay. And we have this terminal kind connecting with this terminal al kind. So this would be our final product. Now, this reaction also involves we have copper to acetate being used here and we have purity in base also involved in this reaction. But again, even though we haven't done the mechanism yet for this coupling reaction, we know that from what we've seen up above the hydrogen on both ends of the terminal all kinds would have been lost. And so those two carbons left behind would connect together to give us our by Alcoa o'neill product that we have here. Now that we've seen this simple example. Question click onto the next video and see how exactly does the coupling mechanism work for the clinton coupling reaction?
3
concept

Eglinton Reaction

clock
4m
Play a video:
Was this helpful?
So the clinton coupling reaction can be seen as being comprised of four basic steps. When it comes to its coupling mechanism. Step one involves deep rotation. Step two substitution. Step three is radicalization and finally step four is demonization. Now if we start out with the proto nation, we're gonna say the slight acidity of the terminal AL kind hydrogen allows it to be deprived donated by the paradigm base. So here we have this slightly acidic hydrogen. Remember that the nitrogen within our paradigm base has a lone pair. It utilizes that lone pair to remove this hydrogen here. When it's removed, carbon holds onto the electrons within the bond. So as a result we create an alka Neid ion. Plus as a byproduct we make parady um ion as our second product. Now by product we're not really gonna be concerned with. Now we head into step two substitution. So the alcan I'd ion that we made in Step one, it's formed during the proto nation undergoes a substitution with copper one acetate. So here this carbon uses its lone pair to attach to carbon which causes the breaking of this bond towards the acetate ion. So we wind up making is we have our all kind here that is now connected to this copper and we have as another byproduct or acetate ion. From here we go into the third step which is radicalization. So the newly formed carbon copper bond undergoes home a little cleavage in order to form an alcon eyed radical. So remember in home a little cleavage, we have equal splitting of our single bond. So this bottle split the terminal al kind carbon will hold onto an electron. This carbon, this copper here uses this electron to actually attach itself to this acetate. Now remember with hemolytic cleavage, we don't have full arrows instead we have half or hook arrows being used because we only have the movement of individual electrons at the same time that this acetate uses this electron to connect to this copper. This copper in the bond takes its electron and holds onto it. So as a result, what we'll have at this point is are denied radical Plus two coppers connected to associates. Now finally we have demonization. So the final step involves the demonization of the two alcan eyed radicals that have been formed. Notice I say to alcon eyed radicals, that's because during this entire process, remember for this coupling reaction we're using two identical terminal al kinds. So all that's happening here to talk to all Kind number one, the same exact thing has been happening to al kind number two. Which is why by the time we get to our fourth step we have to alcon I'd radicals. Demonization can be seen as a form of termination where two radicals joined together to form a new stable compound. So here half arrow because we're moving one electron half arrow because we're moving one electron and now these two are joined together. So this would be our final product. So just remember this coupling reaction is a bit different from the other coupling reactions that you might be used to. It doesn't use a catalytic cycle in order to form the product. Instead, we have the utilization of radicals. As long as you can remember the basic setup for this type of coupling reaction, you can get to the product very easily. But if you need to work out the mechanism, just remember that it's comprised of four steps within its mechanism. We have deep rooted nation substitution radicalization and then finally did memorization to get our by al kamil product.
4
Problem

Determine compounds A and B from the following reaction sequence.

Was this helpful?
5
Problem

Predict the product formed from the following intramolecular Eglinton reaction.

Was this helpful?
Divider