Propose a synthesis of the carbonyl(s) using the (ii) dihydrox...

Question

Propose a synthesis of the carbonyl(s) using the (ii) dihydroxylation/periodic acid cleavage pathways.

(b) Chemical structure showing a carbonyl compound with a benzene ring and a silyl ether group.

Accepted Answer

Welcome back everyone. Another video suggest the synthesis of the following carbonyl compounds using the dihydroxy reaction of an alkene followed by the treatment with meta pero acid. And we're given the two products of our sequence of possible reactions. One of them is one fenny propan and another one is acetone. What we want to remember is how me aperiodic acid is used in the oxidative cleavage because this is our final step. So our final step will involve a dial or more specifically a vicinal dial and this will react with meta per ionic acid to form the required carbonyl compounds. Let's remember that when we consider our mechanism, this reaction will have a specific intermediate with iodine formed. So that one of our bonds will be used in the formation of a pi bond followed by the cleavage of the carbon carbon bond and then the formation of another carbon bond. And that's how we get our two carbon structures. So now if we go backwards, what we noticed is that we want to combine our carbon atoms into a single bond between two carbons, specifically, we're going to introduce a bond between our carbon carbons. So let's go ahead and do that so we can get our dial. Our first step is to just draw the left structure. So we're going to start by drawing a six member. And what we're going to do now is just fill our side chain, 12, we carbon atoms. Now, instead of having that double bond, we're actually connecting that carbon to the carbon atom from the other Keone, we are going to introduce a single bond between them. And what we noticed is that we have two additional metal groups. Now we want to turn it into a vial dial. So specifically, we want to make sure that we add our two alcohol groups. And of course, we want to make sure that they are insist arrangement, especially if they're bonded to a ranks carbon. But in this case, we can have free bond rotation. So it's not that necessary because we can always align them in s arrangement or basically in sin arrangement. That would be more accurate to say, right. So in this case, one of our carbon atoms is not chiral. So it doesn't really matter. We can just say we're adding one of our alcohol groups on a solid line because there's no chiro center and then we can add another alcohol group either on a wedge or a dash. So if we have two possibilities, let's show both of them. Now, for one of them, we will just use a watch. So let's go ahead and draw that watch because we have a coral carbon atom, meaning we must turn one of our bonds into a dash. So let's go ahead and replace that metal group with a dash. Well done. And now let's draw our second possibility for that vicinal dial. Specifically, we're going to simply add the alcohol group on a dash, right. So let's go ahead and add it on our dash bond. Great job. So we have two possible vicinal dials. And now what we want to do is just get the desired alk because the starting material must be an alk. And because the reaction starts with dihydroxy, we have to remember that dihydroxy requires us to use osmium to trioxide in the presence of hydrogen peroxide. And number two, we want to make sure that we break that sate ester using sodium by sulfide in the presence of water, meaning we're using an acre solution, right? And now let's recall that whenever Alkins react with this set of regions, we get vicinal dial. So to get our Alcaine, we're simply going to remove our two alcohol groups and add a double bond between our carbons. Simple, right? Meaning our starting material must be a six member drink to begin with. So let's benzene, let's add that side chain of three carbon atoms. Then let's add the carbon and let's introduce our pi bond. So that must be our starting material. And now that we know our intermediate products. Let's just draw a possible synthesis scheme. So we have chosen our starting with cereal. We want to perform the thin thy hydroxylation using osmium to trioxide in the presence of hydrogen peroxide. And number two sodium by sulfide in the presence of water. That's our first step. And as we said, during the Sendai hydroxylation, we're adding two alcohol groups to our SB two hybridized carbon atoms by breaking that pi bond. And this is where we get our two possible medicinal dials. And when we get these two products, we want to get the desired carbonyl compounds, right? Meaning just as a problem suggests, we're going to use meta per ionic acid. Hio four. And it doesn't really matter which isomer or stereo isomer. We take, we will still get the same two carbonyl compounds. So what we're doing is just breaking our carbon carbon bond or single bond to be more accurate. And then we are essentially turning our alcohol group into a carbonyl group. So our first product will be that benzene ring, a three member chain. And now what we noticed is that bonded to carbon number two, we have our oxygen which now becomes an oxo group or a Keon. And the other product is obtained from the other carbon which has two metal groups attached to it. So, acetone is obtained as the other product and that would be our synthesis, Kim. Great job. Thank you for watching.

Propose a synthesis of the carbonyl(s) using the (ii) dihydroxylation/periodic acid cleavage pathways.
(b)

Key Concepts

Dihydroxylation

Periodic Acid Cleavage

Carbonyl Compounds

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