The following compounds can be synthesized by aldol condensati...

Question

The following compounds can be synthesized by aldol condensations, followed by further reactions. (In each case, work backward from the target molecule to an aldol product, and show what compounds are needed for the condensation.)
(b)

(b)

Accepted Answer

Hi, everyone. Welcome back. Let's look at our next problem. The following compound can be created by performing condensations, followed by other reactions, determine the compounds required for the condensation reaction. So the look, let's look at the compound we have here. So we have this five carbon ring with a carbon group on it. And then at the beta carbon from that carbon group on our ring, we have this other chain where it's bound to our ring that is sort of the central carbon of our chain and that central carbon has Carboni carbons on either side of it. So it's the alpha carbon in between two carbonyl carbons. So we'd say we have an alpha beta dic carbonyl group here. Then one of the carbon carbons has a fenny group attached to it, excuse me. And then the other Carboni group, carbon has just a methyl group sticking off. And then finally, our five carbon ring on the other side of the carbonyl group has a little methyl group sticking off the beta carbon. So when we're looking at, how did we put this compound together, we're probably not gonna worry about that little methyl group, but we're definitely gonna focus on this diar chain here. We know we're focusing in on a condensation reaction. So let's think about these condensations. What's the essence of them? Which is the formation of a new carbon carbon double bond, replacing a carbon oxygen double bond that one of those carbons originally participated in? Well, we don't have any carbon carbon double bonds in our compound here, but we do have in the central carbon of this chain attached to our ring. And I'm gonna highlight this in blue, an activated methylene group, it's surrounded by two electron withdrawing groups. The two Carbonis and we do have a reaction involving activated methylene groups and carbon carbon double bonds. We know that activated methylene groups can participate in a nucleic addition, two alpha beta unsaturated Carbonis. So when we look at our five carbon ring with its carbon eel group, if those alpha and beta carbons originally had a double bond between them, that is a candidate for that nucleic addition of an activated methylene group, that would mean that the bond that was formed draw a little squiggly line across it is the bond between the activated methylene carbon there and the carbon, the beta carbon on our five carbon ring. So let's kind of do a retro synthesis from our original compound to get our alpha beta unsaturated Carboni. So I'm going to put a little retro synthetic arrow there. And we know we would have had our five carbon ring. But now with a double bond between the alpha and beta carbons, I'm gonna go ahead and label them on the ring, alpha and beta and unattached. We would have our little chain here, our, our alpha beta di carbon chain with the activated methylene group and I've still highlighted that in ball so we can keep track of which carbon is which. So now when we look at our five carbon ring, we do have AC C double bond and it is an alpha beta unsaturated Carboni that double bond is between the alpha beta carbons next to a carbon group. So we know that that can be the result of an Aldo condensation. And we are of course, looking for what compound participated in that Aldo condensation. So let's go ahead and keep on going backwards with our little retro synthesis. I'm going to label the alpha carbon in that double bond with a yellow highlight and the beta carbon with a red highlight again, just to kind of keep track of what's going on there. So we're gonna draw our alcohol intermediate that is present in that out all condensation reaction. So here's our five carbon ring and we know that the double bond will now be a single bond. And the beta carbon here in red is what would have been the carbonyl carbon in our first reactant. So as the alcohol intermediate that beta carbon will have a hydroxy group on it in that intermediate and the alpha carbon is just there labeled in yellow. So there we have our hydroxy intermediate. Now to trace the final step back, we know that that alpha beta carbon bond was the bond formed by the condensation. So I'll draw a little squiggly line across it signifying that that's the bond that's going to be broken as we work backwards here. So then again, tracing backwards with our little retro synthetic arrow, we've broken the bond in the ring. It's no longer a ring. So here's our carbonyl carbon that was originally in the ring. It now ends just in a carbon with three hydrogens attached to it. Let's keep going with what was our ring? A little mapple group. But now that last carbon is now a carbon carbon with ac O double bond where the hydroxy group had been attached previously. So again, I'm going to label those carbons that were the alpha beta carbons originally red for the carbon that's now in the C O double bond and yellow for what's now the terminal carbon that alpha carbon for the carbon group that was originally on the ring. So our ring is no longer a ring and our chain has two Carboni groups on it. So we only had one compound participating in a cell condensation reaction. It was this chain here with two carbonyl groups. It reacted with itself to form a ring and al all condensations are useful reactions for forming five or six carbon rings. So it reacted with itself in an al condensation reaction to form that C C double bond, which then participated in the nucleic edition of an activated methylene group to get the original compound presented in our problem. See you in the next video.

The following compounds can be synthesized by aldol condensations, followed by further reactions. (In each case, work backward from the target molecule to an aldol product, and show what compounds are needed for the condensation.)
(b)

Key Concepts

Aldol Condensation

Retrosynthetic Analysis

Functional Groups

Watch next

The following compounds can be synthesized by aldol condensations, followed by further reactions. (In each case, work backward from the target molecule to an aldol product, and show what compounds are needed for the condensation.)(b)

Key Concepts

Aldol Condensation

Retrosynthetic Analysis

Functional Groups

Watch next

The following compounds can be synthesized by aldol condensations, followed by further reactions. (In each case, work backward from the target molecule to an aldol product, and show what compounds are needed for the condensation.)
(b)