Show how you would accomplish the following syntheses efficien...

Question

Show how you would accomplish the following syntheses efficiently and in good yield. You may use any necessary reagents.

(a) acetaldehyde → lactic acid, CH₃CH(OH)COOH

Accepted Answer

Hey everyone and welcome back in today's video we are going to show how the given conversion can be achieved with a good yield, provide any necessary regions, propane al forms two hydroxy botanic asset. The starting material is pro panel so we can just draw our Aldo hide starting with an elder Hyde group. We want to keep in mind that there are three carbon atoms in the parent 123. And the conversion looks as follows. We are going to form two hydroxy botanic acid. So we can start by drawing our carb oxalic acid fragment and then add four carbon atoms to our parent because it's beatnik acid. So that's 1234 at position number two we have our hydroxy substitution. This is one, this is two. So we are going to add O. H. First of all, it's really important to understand that the conversion is not that simple. This is an AL hide this is an asset. We definitely cannot use oxidation because oxidation of algae hides only forms corresponding assets and these two are not corresponding compounds because they have a different number of carbon atoms. This one has three. The asset has four. And in addition to that we have our hydroxy substations. So the conversion would not be so straightforward in order to add that carbon atom and facilitate our thought process. We can use the formation of a night trial and the reason why we want to do so is because it will allow us to get one more carbon atom within our parent and then we may recall that hide religious of night trials allows us to produce assets. So this might really work for us. And let's see how that works. So, first of all, in the first reaction we are going to form our night trial and to do that, we are going to use but ask him cyanide right in the presence of hydro satanic assets. So let's see that. So let's draw what happens in the stop we are using potassium cyanide. I'm not going to include potassium right? Because it's a non spectator, you may use sodium cyanide if you wish, as long as it's not in spectator, that's fine. So we're going to use cyanide in the presence of hydro sonic asset which will essentially protein eight hour intermediate. But let's see how that works. So cyanide will essentially attack the electra filic position. We would break the pi bond and we would form our first intermediate in this reaction. Notice how we may simply troll that cyanide, wanted to carbon. Right? So first of all, let's see that oxygen would have a negative charge because it only has one bond now and let's draw our carbon atoms. So 123. And now the reason why we're using hydro satanic asset is because we want to protein it, that intermediate and this allows us to get our saya no hydrant in this step, we're getting our cyan a hydrant and from here, you should be really happy to see this, notice that we have our ohh substitution we simply want to hide relies our night trial into corresponding asset and this would work for us. We call that whenever you're high, you're performing the hydrolyzed sis of a night trial. Unlisted conditions such as you have our monitors. CN that's your night trial. And if you use acidic high troll as this in particular, H30. Plus, you're going to form a corresponding assets. We're going to have our bonded to C. 00. H. So simply speaking, we're only looking at this part. This is our night trial group and we're going to convert it into a carb oxalic acid. Right? And this would give us the right product. So we can say that in this case, if we use our acidic high troll is us, which would correspond to the following region. Let's add that H 30 plus, we may simply notice that this is our 1234 carbon atoms. That makes sense. Right. 1234. We clearly see that the third carbon atom has O. H. That's fine. Now for carbon number four hour night trial becomes a carb oxalic acid. Right? So that definitely works for us, meaning we have proposed a feasible reaction to this problem. So let's summarize our steps after we clearly see our analysis now. So we are starting with our Aldo hide. So that's propane L the first step, as we said, we are going to treat it with potassium cyanide in the presence of hydro satanic assets. So let's suppose we use K C N H C N and this forms the cno hydrant we were referring to in other words, we are going to form the following structure where we have our nitrile group and then we have our oh age group which is formed. It's the fact that we have HCM present in the mixture. So it's protein, it's negatively charged oxygen. And when we get our santa hydrant, we need to make sure that we hide relies the night trial for these purposes we're using acidic work up and this night trial group is converted into an asset. So we're just redrawing the fragment. Now we will have 1234 carbon atoms in the parent 1234 position number four. Not in terms of high pack, right, but just from left to right, the fourth carbon atom from left to right essentially has our carbon that is now converted into a car book silic acid, right from night trial to a car book silic acid. So that's our car book silic acid group and the adjacent position has an a wage group. This is indeed the product that we wanted to get and we may label this sequence is our final answer based on the sequence. The correct answer to the multiple choice question is the however, if you have any questions don't hesitate to leave a comment down below. Thank you for watching.

Show how you would accomplish the following syntheses efficiently and in good yield. You may use any necessary reagents.
(a) acetaldehyde → lactic acid, CH₃CH(OH)COOH

Key Concepts

Aldol Condensation

Reduction Reactions

Reagents and Conditions

Watch next