Starting with (R)-1-deuterio-1-propanol, how could yo...

Question

Starting with (R)-1-deuterio-1-propanol, how could you prepare

c. (R)-1-deuterio-1-methoxypropane?

Accepted Answer

Hey, everyone and welcome back using R one DS One heal as the starting material. How could the following be produced? R one D, Ceo One Metox hack. Now to begin with, one of the most important things for us is to get our structure right? So the starting material is hexen. Let's draw six carbon atoms in our chain. 123456. And because it says one, we are going to add an O H group at carbon. Number one, We are also going to add the ethereum at carbon # one. And also let's expand the implicit hygiene at that same carbon because position number one has four different substitutions and it has an R configuration. We have to recall the Ingle pre log rules. So first we have to assign our priorities. If we look at all of the atoms bonded to carbon, one of them is deuterium. Another one is hygiene. The other one is oxygen and the final one is carbon. Since oxygen has the greatest atomic number, it'll be priority number one followed by carbon, followed by the cerium. Even though the serum has the same atomic number of one, just as hygiene, it has a higher mass. So it gets priority. Number three, hygiene gets priority number four. So simply we got our priorities and we are going back to our structure. We are just going to label our priorities one for oxygen, Two for carbon three for deuterium and four for hydrogen. According to the rules, if we want to assign the rotation directly, we can just add a dash for priority four. So let's add a dash for hydrogen and then a wedge for priority number one, Let's try to assign our configuration. So if we trace our path from 1 to 2-3, we get a clockwise rotation, which indeed corresponds to an R configuration. Well done. So we have drawn the correct structure. We will just redraw it once again, 1, 3456 we are going to add O H winding up the cerium on a solid line. And then he chan pointing down from this, starting with cereal. We want to form another structure. And the main difference is that the product that we are forming are one deter one meth. He Simply has a Mathy substi instead of a wave. So we're going to replace a wage with OC three. Notice that the configuration has not changed, it's still are. And because the atom that is wanted to, the chiral position is still oxygen, there is no necessity to change our wedge to anything else. It's still a wedge right. It's exactly the same configuration. So we have depicted our reaction and we have to think about possible ways to perform that conversion. First of all, we are converting an alcohol in Easter and because a age is such a poor living group, the first step in our reaction could be conversion of an alcohol into an alkyl chloride that has a much better living group, which is chlorine To do that. We are going to use thy chloride SOCL two in the presence of pine and protein. Here is really important because it will allow us to have an inversion of configuration when we add to our structure. So let's see that in this reaction, let's recall that the O H group is replaced with chlorine, but there's also an inversion of configuration. So in the intermediate product, we're getting chlorine pointing down And hygiene pointing up. So we're swapping priorities one and 4. Now we want to get an Easter, we have a good living group and we can use an essence to reaction because we once again want to reverse our configuration to get a filed product For an SN two reaction. We need to use an appropriate nuclear file. And in this case, that would be oxide OC three negative because that's what we're bonding to our choral position. So the negative charge on meth oxide would essentially attack the electro pic center, followed by the loss of the lead group, this is a backside S X. So it allows us to reverse our configuration and this is how we get our ether. So this, this is one of the pathways to perform the required conversion. And we can label this in green and we can move on to another method. So because you're forming an ether, another way to perform that conversion is via the Williamson ether synthesis. Let's draw out starting material once again. So 123456 carbon atoms. Now our age group is signing up deuterium is on a solid line. And hydrogen is pointing down to perform the vane synthesis. We first will want to deproteinate our alcohol. If we deproteinate our alcohol using a strong base such as sodium hydride, for example, we can simply state that hydrogen bones oxygen within the alcohol group will be removed by the hydride anion H minus, it attacks the acidic proton and we're forming our Elcock at N M. Nothing happens to stereo chemistry because we're only removing the proton, we get the oxide and iron. And now this is where the Williamson ether synthesis comes in. We want to use an appropriate substrate and that substrate must be a primary substrate with a good living group because we want to form oxide, we simply need to use methyl chloride, for example, or chloro methane. So we are going to say that if we use CH three CL, the negative charge on oxygen would essentially attack the electro Pyle carbon followed by the loss of the leaving group. And this is how we get our final product, which is ether, we may add an additional arrow, clearly illustrate that for this reaction, we are using Chloro Methane CH three CL and through the final product. All right. So we got our final product and this is another way how we can perform this conversion. So we are going to label it in another green box. And based on the two synthesis paths that we have described here, one of them was through two successive two reactions and another one was through the Williams and Ether synthesis. We may simply state that the correct answer. So this multiple choice question is E both B and C are the correct pathways. Thank you for watching.

Starting with (R)-1-deuterio-1-propanol, how could you prepare
c. (R)-1-deuterio-1-methoxypropane?

Key Concepts

Stereochemistry

Nucleophilic Substitution Reactions

Deuterium Labeling

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