Radical Synthesis - Video Tutorials & Practice Problems
The following few examples are cumulative. If, by chance, you happen to not know some of these reactions, don’t freak out. Just try your best with the reactions you do know.
Predict the MAJOR product of the following multi-step synthesis.
1
example
Predict the MAJOR product.
Video duration:
4m
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All right. So the first reaction would be what? This is what we call a radical halogen nation or a radical Bram in ation. And remember that this is actually the only starting point I have for an Al cane. I'm starting with an Al cane, so I really need to start from there. So let's go ahead and attach the bromine. Where would it go to the tertiary position? Okay, now I have L d a L d. A. With a tertiary alcohol. Hey, lied is going to do what? This is a flow chart question. When I say flow chart, that means it's my flow chart that has to do with substitution elimination on looking those chapters if you want to know more about that flow chart, But what that would be is that would be ah Hoffman e to Okay. And that should be something that's pretty comfortable to you guys at this point, because we've done it a lot. Okay, So Hoffman e to basically any bulky base would do Ah Hoffman e too. So that means that where should I make my double bond? I actually have two different double bonds available. I could use the alphas. I'm sorry, the beta hydrogen is here that are both the same. Or I could use the beta hydrogen here. Okay, I have to go for the one that's gonna give you If it's Hoffman, that means less substituted. So I would actually make adorable in that. Looks like this. Okay, Because that's the least substituted product that I would get. And it's asking for the major product. Now, in the next step, I'm doing HBR and peroxide. Just remember what this would be. Well, this is gonna be a radical hydrology nation, and this was special because what did it dio If you guys remember, it gives you anti mark alcohol. Hey, let's Okay. It's a very important reaction to remember for that. So what that means is that if I'm gonna add the br somewhere, the place I wanna add it is actually down here. Makes sense. Cool. So now I have my ante Markov Nick off, bro. Mean now My last step is n a O E t. This If I have a strong nuclear file, have a good leaving group. This is a flow chart question. Again, let's go ahead and use the flow chart. So, first of all, I always just drawing numbers here. So the first question is is my nuclear follow negatively charged or neutral? So this would be negatively charged because any o. E. T. Is gonna have a spectator ion. Okay, so that means I go down the left side of my chart. So, for two, um, is this going to be a bulky base? New? Okay, there were three bulky basis I had you guys memorize. This is not one of them. Okay, so that means I go down to the third question. Third question is, what kind of alcohol highlight do I have in this case? What does it look like? This is a primary alcohol. He lied. Is that gonna favor any mechanism Yes s into So this is gonna be an S n two reaction. Okay, so I have an s and two reaction. I'm reacting that with oh, e t. So I'm gonna get a backside attack and my final product for this stage or for this molecule. I'm sorry for this Reaction would just be this. Oh, e t remember that? E t just sends for Ethel. So you could have drawn that as a to carbon stick or a ch three ch ch two ch three Whatever you want. But this is my final product. Notice how my functional group at the end is an ether, and I started off with an Al cane. Isn't that awesome? So I could totally change this molecule just with four simple steps and hope doesn't seem simple. But just saying that's the whole point of organic synthesis is to take boring out canes and make them actually functional. Okay, so let me know if you have questions on that, let's move on to the next question once again expects us to do everything on your own. Try not to get stuck, and then I'll give us the answer.
Predict the MAJOR product of the following multi-step synthesis.
2
example
Predict the MAJOR product.
Video duration:
4m
Play a video:
All right. So what was this first reaction HCL on a double bond? That would just be a regular hydrology nation. Okay, what that's going to do is it's going to give me a Markov Nankov al Kyohei light. Okay, so my first step, I just expect to get a c l here. Now. Usually we draw the mechanism for mechanism for these, but notice that this car Bacharuddin wouldn't shift because it's already gonna be tertiary. So I don't have to worry too much about the mechanism. The mechanism is really important when you a carbon copy and could shift. But in this case is not going to now I have terp. You talk side. What's that going to do to a tertiary? Al Kyohei lied. This is a flow chart question again. So I would say Okay. Is this a negatively charged malt nuclear file? Yes. Is it a bulky base? Yes. TV talk side is one of the bulky bases, so there's gonna be ah Hoffman, be to Okay. Hoffman e two means that I'm gonna prefer the less substituted double bond, so my product should actually look like this. Okay, so I'm going for the less substituted. If I made it go down or up, that would have been more substituted. That would have had more our group, so that would have been a bad choice. Now we've got CL two over water. Do you guys remember what that ISS that is gonna be a halo hydrant formation. Okay, this is one of the addition Reactions you need to know. Okay, So the way that a halo hydrant formation works is that you're going to get a chlorine with a positive charge. That's gonna be your intermediate. And remember that then water comes in and attacks the Markov niqab location. Okay, so we wind up getting at the end of that mechanism. I was just kind of trying to draw a shorthand for you guys, you'd remember. Is you get, um, obviously, like an alcohol on one side, and you'd get an anti facing halogen on the other, so notice that they have opposite stereo chemistries. Okay, so that's from the whole halo hydrant. Okay, Now, the last step is Anne Ohh. What does any of which, due to a halo hydrant, Do you remember? This is a very, very particular reaction. Okay, If you don't remember it. I'm sorry. I'm not trying to be mean, but it is an important reaction for you guys. This is actually gonna be, ah, form of hip oxidation. How? Okay, we'll remember. Approximation means I'm making up oxide. Remember, there's two ways to make a pox sides. We could use proxy acids, which would just add directly to the dull bonds. So if I wanted to use a proxy acid right here, I could Okay, But once we have the halo hydrant, I could also use a base to do what we do. Call an intra molecular sn two. Okay, So just to remind you of this mechanism, what winds up happening is that might always negative, pulls off an age and gives me something. Looks like this seal here and an o negative here. So notice that now I have a nuclear fall and 11 group right next to each other. So these wind up doing a backside attack on each other, and what I wind up getting for my final final product is an a pox side that looks like this, plus my leaving groups seal. Okay. And that is actually my product here. My product is this a pox side. Okay, I could have even made this harder. Because remember that hip oxides open with an acid catalyzed on the base catalyzed method. I could have made you do that as well, but we didn't. I took it easy on you guys. We just made the A pox side. But just letting you know these are all common synthetic pathways that you need to know. Okay. And noticed that we were able to use now were you able to use a lot of radical reactions in them? Okay, cool guys. So I hope that made sense. Limit if you have any questions. If not, let's wrap this one up.
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