Show how you would convert 3-bromocyclohexanol to the followin...

Question

Show how you would convert 3-bromocyclohexanol to the following diol. You may use any additional reagents you need.

Accepted Answer

Hi everyone and welcome back in today's video, we're looking at this problem which reads right, a synthetic route showing how you would transform to chloral cycle pencil into the dial shown below. We are starting with an alcohol. In addition to that, we have a close substitute print and we're forming a word similarly looking substance. But notice that in particular we have three additional carbon atoms in this position as well as an alcohol group. We wish to think about a possible pathway to keep that alcohol group and produce a new one with additional carbon atoms and it essentially implies that there will be a Green Yeard reaction involved. One of the primary goals will be to use a Green Yeard reaction. We may now plan our route because a grin ERC reaction will not really proceed in the presence of these hydrogen. We will want to protect it. So we may plan our route as follows. Step one, let's just protect that alcohol group. During the protection step we may use TMS which is detrimental, silo chloride, tMS cl as well as a base such as tri ethyl amine, which will essentially allow us to protect the alcohol group by forming a bond between oxygen and silicon and then the protein aiders hydrogen using tri ethyl amine that would essentially form a protected group at this position. Number two. After we protected, we noticed that we have a chlorine atom and disposition so we may form the green yard region. If we already have chlorine here, all that we need to just add magnesium in ether recall that if we see halogen such as chlorine or bromine, adding magnesium and ether was form a green yeard region at this position in particular, number three. When the granular gray gender is formed, we will need to add three more carbon atoms. So we need a carbonell group. Two methyl groups at these positions, meaning the best idea is to use a key tone. So we are going to react number two. The product that we will form from number two, that would be a Greenock region with a key tone that must have two method groups and this is acetone. Now remember that during that reaction we will form an alc oxide and iron. So for step number four we will need to use an acidic work up to reproduce the alcohol group. That would essentially allow us to get this sort of transformation going from chlorine to this alcohol. However, as a final step, we wish to remove the at the protecting group. So we are going to use the deep protection which generally can be performed using Bu four. Um This is an ionic compound, it's called de tribute tal ammonium fluoride and it essentially allows us to d protect the alcohol groups or the original otms will be changed into the starting alcohol group. So now let's use that logic and let's perform our synthesis in the first step if we just read through our original substrate, we have our cycle fencing ring, we have the alcohol group at position number one position number two has chlorine. So we are going to use the protection stop. In other words we need a protecting group and that will be T M S C. O. Our first region is detrimental silo chloride in tri ethyl amine, which is a base that would allow us to d protein ate it. So oxygen would form a bond with silicon chlorine would leave and also nitrogen would be protein ate it to form our protected group. We are going to indicate that the product that we get in this stuff is simply oh T. M. S. That's our first product. Now the second step is to form the greener creation for our reaction and we already know how to do that. We are simply using magnesium in the easter. Magnesium forms a bond between the carbon atom and chlorine. And that said we may troll our product for this stuff. There will still be OtMS group. It's protected. And now over here we have magnesium and chlorine, that's our graveyard region now. So we are ready to add our carbon eel compound. And in particular we wish to use acetone because we need three carbon atoms, meaning if we if we use acetone we may draw its structure there will be an attack by these electrons onto the electra Phillip carbon. And we would also break that double bond, we would form the elk oxide and I and at this stop, let's draw it now. Otms stays. However, here we are forming this structure, oxygen will have a formal option, will have an actual negative charge because we are forming a new bond and breaking another. So the pie elections will be transferred on oxygen as a lone pair, making it negatively charged. Now our next step is the acidic work up. We are going to use acidic conditions and water that would be a church to you in acidic conditions. And we would essentially protein ate our structure. We may now say that the structure that we get looks as follows the protective group. And then for this one we would have an alcohol two method groups. And the wage group would now be protein ated the Alcock side that we had previously now forms an alcohol the world. Last step is the deep protection stop. We want to get rid of that protective group And still that we are using Bu for N. F. The tribunal ammonium fluoride, essentially what it does. It d. Protects your group and it restores the original alcohol group. That's what we did. We didn't want to affect it in our reaction. So we definitely need that final step to form our final product. So let's draw our final product. We now have an alcohol group here restored in the and then this additional substitution which is now ohh! Great job. So this is our reaction sequence. We may label it as our suggest that synthesis route. and now we are pretty much ready to conclude that the correct answer to this multiple choice question is D. However, if you have any questions, don't have states, leave them down below and thank you for watching.

Show how you would convert 3-bromocyclohexanol to the following diol. You may use any additional reagents you need.

Key Concepts

Nucleophilic Substitution

Reduction Reactions

Stereochemistry

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