To this point, we have seen four reactions that can be done by...

Question

To this point, we have seen four reactions that can be done by Gilman reagents. What are they? What do they have in common?

Accepted Answer

Welcome back. Let's take a look at our next question. It has two parts, number one, name, four reactions that can be done by Gilman reagents. And number two, what do they have in common? Aside from the use of a Gilman reagent? And we have multiple choice options with different options for reactions, different options for what they have in common. So we're going to put those aside and look at them more closely after we think through Gilman reagents and what my reactions they might have rather than just reading through everything. So, first of all, let's remember what a Gilman reagent is. It's an organo metallic compound, specifically organo crate. It has the form R 22 R groups cul I. So it has a copper, a negatively charged copper and a positively charged lithium. And these are very useful for forming new carbon, carbon sigma bonds, but they have certain types of molecules that they react with and certain that they don't. So the Gilman reagent will react with relatively weak polar liable bonds. This includes CX bonds where X is the halogen uh and cross coupling reactions and co bonds in strained rings. But a Gr doesn't react with polar functional groups containing strong bonds like ketones, aldehydes and aster. So let's look at that group of the types or that list of the types of groups that our Gilman re agent will react with and thinking about what they all have in common. So I'm just going to scroll down here and we'll scroll back up to look at our answer choices. After we work through these reactions, Gilman reagents can react in cross coupling reactions with primary alky heli where I knew our group replaces the hide. So if our Gilman reagent is for instance, will show two isopropyl groups, I'm going to show them in red. So we can see where they add on to our molecule attached to the C minus L plus in the center. One of those isotopy groups will add on as an R group in a cross coupling reaction. So for instance, we can have chop propane here. After reacting with a Gilman reagent, we'd end up with our 123 carbons with then a new bond two, the isopropyl group that was on our Gilman reagent. So there's that's a cross coupling reaction. They can also open oxide rings, a lot of ring strain and those rings relatively weak bond, it will open it by adding to the uh adding our group to the least substituted carbon. So if we have this oxide ring with two more carbons on it, it will open up by adding at the least substituted carbon. And we'll end up with our isopropyl group attached to first carbon from the ring. Second carbon from the ring, the ring is opened up so that carbon has an alcohol group. And then the other two carbons that were on that molecule, they can also react. And let's scroll on down here with alcal halides or with acid ides. So if we have, for instance, we got carbon Bronto carbon oops. So carbon one, carbon two with AC C double bond and then chlorine, when we react with our Gilman reagent, we'll replace that chlorine with that our group. That's on a Gilman reagent. So with that isopropyl group on there, it replaces the chlorine and then it can react with an acid hide. So draw carbon carbon with a carbonyl group and then a chlorine. And again, the isopropyl group there can replace the chloride. So both times adding that new R group and finally can react with alpha beta unsaturated Carbonis. So we can show a carbon bonded to a carbon. So carbon one carbon two with a double bond to carbon three to a carbon or carbon. And when we react that with a green yard reagent, the isopropyl group will add on to one of the carbons in the double bond and you'll end up with that isopropyl group added on the double bond being broken and then we still have our carbonel bond there. So again, we've added an R group to that CC double bond. So let's think about what all these have in common and scroll back up to our answer choices with these reactions in mind. So let's look at choice A, it says that for the reactions, number one cross coupling oxide opening substitutions of ketones. But we know that Gilman regents don't react with ketones, they have a too strong a bond. So choice A is out. In addition, choice two says all the reactions have reactions with double bonds but alkyl halides do not have double bonds. So choice a wrong there in two different ways right away twice. B says cross coupling oxide opening substitutions of acid chlorides. That is correct. Conjugate addition to alpha beta unsaturated Carbonis. So four reactions that Gilman reagents carry out. And number two says all the reactions produce alkanes, but that is not correct because when we look down, we know that we have an alcohol group when you open an oxide ring and you have ketones, when you react with alcal halides or with alpha beta unsaturated carbonyl. So the question is, what do they have? The answer to what they have in common is incorrect in choice B. So let's cross out choice B and Choice C says, or number one cross coupling oxide opening substitutions of acid chlorides conjugate addition to alpha beta unsaturated Carbonis. That's correct. And then number two says all the reactions add our groups to the molecules. Well, that is a correct description of what is going on in these reactions. So we have a correct answer in choice C to be thorough. Let's just double check. Our choice D option says for number one cross coupling oxide opening. But then it says substitutions of ketones and again, ketones that carbonel bond is too strong and that will not react for the Gilman reagent to choice D incorrect. In addition, it also has for number two, all the reactions produce alkanes, as we said was not correct. So the four reactions that can be done by Gilman reagents and what they have in common is choice C for the four reactions cross coupling epoxy opening substitutions of acid chlorides and conjugate addition to alpha beta unsaturated carbo. And for number two, all the reactions add our groups to the molecules. See you in the next video.

To this point, we have seen four reactions that can be done by Gilman reagents. What are they? What do they have in common?

Key Concepts

Gilman Reagents

Conjugate Addition

Cross-Coupling Reactions

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