Kumada Coupling Reaction

in this video, we're going to take a look at the Coumadin coupling reaction. Now the kumara coupling reaction involves the coupling between a carbon Halide and a re agent that we've used numerous times in the past. The Green Yards re agent. Now the reaction uses a palladium or nickel catalyst in the formation of predominantly by a real or buy vinyl products. Other types of products can be created, but those are usually the two that we're aiming for now here, the use of a palladium or nickel catalyst allows for stereo selectivity with the graveyard re agent. Now we've used graveyard re agent and other reactions before. But with this reaction, the catalyst that we employ allow us greater control over the the configuration of our final product at the end, if we have now keen, we can use certain types of grain yards to give it either an E or a Z configuration um for our product. So we have greater control over our product stereo chemistry. Now the kumara coupling reaction, it can mirror the generic form of a cross coupling reaction. Now, in a generic cross coupling reaction we have our one X, which represents our carbon Halide. We have our 2C, which represents our coupling agent, we use a transition metal catalyst here where m represents our transition metal al represents the number of Liggins attached to it, which usually is two or four. And through the use of this catalyst, we can combine our one with R2 to give us our coupling product. Now see X would just be our byproduct formed within this uh generic coupling reaction now going over to the Coumadin coupling reaction. We see that we still have a carbon Hallett involved. And then the R one of our carbon Halide will either be a vinyl or in a real group. Then we have as our coupling agent. We just have our Green Yard re agent. And here the R two group of the Green Yard region is represented by vinyl and a real or an out Kiel group. Then we have the sea portion of our coupling agent is represented by MG X. Or X. Is Cl BR or I. And then finally we have X. That is part of the carbon khallad as usual, it's represents it represents chlorine, bromine, iodine or some trife late group. Now through the use of palladium and nickel catalysts, we have our coupling agent or coupling a product being formed here and then this is just our byproduct. So if we're looking at it through a simple lens, what what does it look like that's happening with the Coumadin coupling reaction? Well, it looks like the X. Of the carbon khallad and the MG X. Of our Green Yard re agent. They're both being lost. Right? So they're both lost and then R one and R two that's left behind. They combined together to give us our final coupling product. So we're gonna take this simple approach to help us figure out what our products will be for these reactions after that. We'll go into greater detail on how we can affect the type of stereo chemistry our products will have at the end, so click on the next video and take a look at the example how we approach it to get to our final answer.

So here we need to determine the product from the following kumara coupling reaction. Now, basically what's happening is we have the halogen that is part of my carbon Halide. Therefore this is our one and then we have the MG X. Part of our Green Yard. So this is our to their lost and then R one and R two are combined together. We do this with the use in this particular case through a nickel catalyst. So what's going to happen for our final product is we're gonna have our our one group and we're attaching to it are methyl group, which is just me. So we just made an al keen as our final product here. In this case we didn't make something that is more substituted or more conjugated rather. But this is the product that we would get in terms of this reaction. Remember it's pretty common for Green Yard reagents to use in our keel group for its are two portion. So in this case we're making in our keen at the end. Now that we've seen this example, click onto the next video and let's take a look at how stereo selectivity plays a role in the coup Mata coupling reactions.

So when it comes to the Coumadin coupling reaction, we have to take into account stereo selectivity as well as chemo selectivity. Now for stereo selectivity, we're gonna say the stereo chemistry of a vinyl khallad is maintained when our keel Green Yard reagent is used in the reaction. So in these two reactions we have ethyl as our our keel group. That is part of our Green Yard re agent that ethel represents our two. And then here we have our vinyl khallad, so that represents our one. We're going to maintain our E and Z configuration. So here we have our our one that halogen that br gets replaced by the ethel and we're gonna maintain the Z configuration. So here goes fo here then for this one it's E. So we have to maintain that. So the apples here. So when we're dealing with in our keel Green Yard re agent and a vinyl Halide, you're gonna maintain whatever the E or Z configuration is of the vinyl khallad. Now when you're using a vinyl or Real Green Yard re agent, then you're gonna get a mixture of products. Here we have ph which is an abbreviation for Benzene. So we're dealing with in a real Green yard re agent. And here we have a zl keane. The ph which represents my R two group will replace the cl this all keen portion is my are one group. So here we're going to get a mixture of products. So we'll get one product where the Z configuration is maintained. But then we're going to get a second product where we get the opposite in this case. E now, besides stereo selectivity, we have to pay attention to chemo selectivity. We're gonna say the Green Yard re agent does not readily couple with a real or a real chlorides. So on this uh benzine ring and the benzene ring represents our our one group, we have chlorine and we have bro mean again, the been the R two group of the Green yard, which is this. Benzene ring will not be able to displace this glory. So instead it's going to go after the bro, mean, it's gonna kick out the bro, men take its place. So what we're gonna get here is our benzene ring with the seal still attached and that B. R. Has been displaced by this benzene ring. So this would be our answer here. So remember for the Coumadin coupling reaction, it's great because we're utilizing a re agent that we're accustomed the scene in the form of green artery agent. But we have to pay close attention to ideas of stereo selectivity and chemo selectivity to get our final coupling product