Starting with benzene and any other reagents you need, show ho...

Question

Starting with benzene and any other reagents you need, show how you would synthesize the compound shown here. (Hint: Consider a Pd-catalyzed coupling for the final step.)

Accepted Answer

Hey everyone and welcome back in today's video, we are going to show how this compound can be synthesized using benzene or any other required regions. The synthesis of the following compound may require the use of a palladium catalyzed coupling reaction as the final step. Because the coupling reaction will be the final step. We are just going to think about the primary and the initial steps to produce a given structure. Indeed, it has benzene. So our starting material can be the benzene ring. Now, dispensing Rain contains two substitutions at positions one and four because position number four contains a substation that has a double bond. Right? That's our L king. We are going to add it using a coupling reaction because coupling reactions allow us to couple Elkins with Ariel substitue ints. Right. So that works for us. We are definitely not going to worry about this one yet, meaning first of all, we want to take care of the isopropyl substitute parent and that would work for us. Right. Because we're then going to add another substitution at position number four and it's Ortho and power directing. So let's begin by adding our isopropyl substitution. And to do that, we are going to use the Friedel crafts reaction. Right? We can say that the first reaction will be the Friedel crafts calculation. Now we have two choices. We can either immediately use two chloral propane. Right? Because you're noticing that we're adding an isopropyl group. Or you can even use one chloral propane because still the electro file generated will undergo rearrangement into a more stable secondary carb. Okay, Ryan. and then the electro file will still correspond to the same structure and you will achieve the same outcome. But for simplicity, let's just choose the first one because it resembles our structure. And it's easier to visualize without any extra steps. And we also want to make sure that we are including our Lewis asset, which is aluminum chloride. Recall that in the stop, we're essentially creating a bond between our carbon from benzene ring and our carbon bonded to the leaving group. Right? So essentially we are creating a bond between this carbon and that one. Let's draw the structure for our pretty doll crafts reaction. We are essentially immediately bonding our isopropyl substitution and that works for us. We can now think about achieving that coupling reaction but before we do so we want to understand how a coupling reaction works. So let's see that the Suzuki coupling reaction can be summarized as follows. Organa boring reacts with art. We bonded to ax. Don't worry. We will define the nature of each substitution just in a bit the regions that we need to use our palladium in the presence of base. Let's suppose sodium ether oxide and heat. This allows us to couple R one and R three. Now let's recall that our one from here and our three from the other structure. They might correspond to aerial groups. Al keen or alkaline. Okay, now are two generally would be hydrogen or an L kill group in our reaction, we are just going to label it as our because it doesn't matter whether we add hydrogen or an alcohol group. Right? It's not really important for our main product. And now for acts, we're going to use bromine or iodine. Keep in mind that chlorine is not used because chlorine requires special conditions for activation. So we want to avoid chlorine here. Okay, so we understand how our reaction works essentially. Our goal now is to form organa boring before we can couple it. Okay, so to do that, we are first of all going to add room into our structure and that's not really booming that we're going to use in our second structure. We're going to produce organic boring. The reason why we're adding roaming first is because we want to replace it with lithium and then you will see what happens afterwards. Just in a bit essentially we want to perform the domination reaction. We call that for this reaction. We are going to use bromine in the presence of a Louis Asset Iron three bromide. This allows us to achieve the product in which Ortho position now will contain como substitution. Keep in mind that an L kill group is Ortho and power directing. Right? So to state accurately, that would be work the position over here and power over here and the major product is formed that at the power opposition. So this is our power position. Okay, the major product is formed at the power position because the alcohol group is slightly hysterically hindered. So the power product is preferred. Now we are going to say that we are going to replace that hydrogen from the power opposition with booming. Now let's draw our ring with an isopropyl substitution. Now moving forward, we can essentially treated with lithium two equivalents of lithium would allow us to replace blooming at this position with lithium. So let's do that. So we're going to say that for this reaction, we need lithium two equivalents and this gives us a very similar structure. But now instead of roaming we have lithium bonded to the benzene ring. The reason why we needed to produce this organa lithium region is that if you recall treatment of this organic lithium regent with cata cold boring would allow us to achieve the formation of our organa boring. And essentially we are going to replace lithium with this fragment of B O. R two times right where our one will correspond to our aerial substitution. So whenever we treat organa lithium with category boring, we're going to get our organa boring for the coupling reaction. This R one corresponds to the whole fragment over here. Right meaning we are going to get the following structure, we can draw our benzene ring. We are going to replace lithium with be right born is getting bonded to that carbon with two R groups. Keep in mind that are here is either hydrogen or an L. Kill group. Okay. And then we have our isopropyl group and now we are ready to perform the coupling reaction because we have our organic worrying. We simply need to make sure that our three contains an L. King because that's how the coupling reaction works. And we already know what kind of elkin we're going to use here. So if we draw the reaction arrow, remember that the supposition that we are bonding will have a double bond to begin with. And then we have a three member chain. The only thing we need to do is just to choose that acts as we said. It can be blooming or iodine. So let's choose brahman. Let's keep in mind that we need to use the palladium catalyst in the presence of sodium east oxide and heat. And as we know, we are forming the bond between these two carbons and greens. So basically that carbon atom and this one right based on the coupling reaction, we said we are bonding R one to R three. Okay, so we are going to form that carbon carbon bond. We are going to remove the Boren and broom in fragments and we are just going to perform the synthesis and get our coupling products. So that will be our benzene ring. We can draw the isopropyl group. And now here we are bonding our three member chain where the double bond starts at the very beginning. So that's the first carbon between number one and number two, we have our double bond and that's indeed the product that we wanted to form. Right? So that means this synthesis works for us. Let's label all of the steps so we can clearly understand what happens. So let's review them. First of all, we performed the Friedel crafts calculation at A. D. Isopropyl substitution that is Ortho and power directing power will be the major product. And then we are performing collision nation with romain adding it to the power position just as we said. Because that would be the major product to equivalents of lithium allow us to replace roaming with lithium. The reason why we needed an organ a lithium region is because that is because when we are treating it with category boring we're achieving our organic boring for the Suzuki coupling reaction and then we're choosing an appropriate elkin right to make sure that we are coupling it with the aerial fragment. Now we have our good leaving group bro. Mean keep in mind that chlorine cannot be used because special conditions are required. So we're performing that coupling reaction in the presence of palladium, our base and heat where we are bonding these two green carbon atoms right? And then we're getting our final products. So this would be our synthesis scheme. Let's label this as our synthesis scheme. And now based on the synthesis, we can conclude that the correct answer to this multiple choice question is B. However, if you have any questions, don't hesitate to leave your comment down below and thank you for watching.

Starting with benzene and any other reagents you need, show how you would synthesize the compound shown here. (Hint: Consider a Pd-catalyzed coupling for the final step.)

Key Concepts

Electrophilic Aromatic Substitution (EAS)

Palladium-Catalyzed Coupling Reactions

Reagents and Reaction Conditions

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