Predict the products of the following Diels–Alder reactions.

Question

(c) Chemical structures of two reactants for a Diels-Alder reaction, labeled with their molecular formulas.

(d) Chemical structures of two reactants for a Diels-Alder reaction, including methyl groups and a cyano group.

Accepted Answer

All right. Hi everyone. So for this question we must draw the structure of the major products and the given chemical reactions. And it appears that the reactions we were given um are actually deals older reactions. So if you recall deals all the reactions, what they do is that they form a six member ring by combining a dying with a Diana file. So a dying is a molecule that has two double bonds separated by a single bond. And a Diana file is a separate molecule with a double bond that can react with the dying. So on the bottom here, I'm going to scroll down to give myself space on the bottom here. Why I went ahead and I redrew our starting materials for both parts A and B. Just so that you can see them a little bit better. So let's get started with our mechanism. But in order to do that, I'm actually going to number the carbons in both are dying. And Diana file that form the six member ring. So on our dying, I'm gonna label um one through four. And in our Diana file, I'm gonna go ahead and label five and six. So When I said earlier that the Diana file reacts with the dying, that's exactly what happens right because the pi electrons of carbon six are going to go ahead and attack carbon one and the double bond in between carbons one and two is going to go ahead and jump in between carbons two and three. Therefore the double bond between carbons three and four is going to jump as well and it's going to go ahead and attack carbon five. So we end up with a six member ring like, so I just want to make sure I keep the colors consistent so that you guys can see where everything is coming from. Right? So this is our six member ring and I'm going to re number our carbons. These four carbons are from the dying and these last two are from the Diana file. So now we have our six carbons and notice how we now have a double bond in between carbons two and three because the double bond that was initially in between carbons one and two um jumped over but we're not done right because we actually have substitutes here, we have a methyl group on carbon three and we have a C. O CH three on carbon six. So I'm gonna erase the labels for three and six. Or actually I'm gonna go ahead and erase all the labels Just so that you guys can see clearly the substitute prints. So that's our method group on carbon three. And we have our C. O CH three on carbon six. So that's it for part one and now we can proceed to part two and do the same thing. Right? So, I'm going to once again label the carbons that form our ring. I went through four is on our dying And five and 6 are on our Diana file. So now, same thing, Carbon six is going to attack or rather the pi electrons are gonna go ahead and attack carbon one. This double bond in between carbons one and two jumps to two and three. And the pi electrons of this double bond between carbons three and four goes and attacks carbon number five. So this is um this is going to be our six member ring. There are four carbons from the dying and these are our remaining two from the Diana file. But once again, we're not quite done right? Because we do have substitue ints and those substitue ints need to be addressed. So, let me just label our one through six just so that you guys can see what's going on. But notice how we have both a fennel group and and all the hide. We have an all the hide on carbon six. And we have a final group attached to carbon one and another fennel group on carbon three. So, there are actually two possibilities for um The positioning of the substitutes on Carbons one and because of this attack of electrons. Right? So because um because we now have a six member ring instead of a double bond, it's not going to be plainer anymore. So we are going to see some stereo chemistry and there are two possibilities. So let me just erase the labels very quickly like that. And I'm going to start by drawing our final group on carbon three because that orientation does not change Because of this double bond that we have over here in between Carbons two and 3, keeping carbon three planer. So like I said before, there are two possibilities for our substitue ints. One possibility is that both of them are above the ring, like. So both of them can be above the ring like. So or and I'm going to scroll down to give myself the other um possibility here or Both. Subsequue ints on positions one in three can actually be below the ring. And I'm gonna show you what I mean by that in a second. Let me just redraw our Fennel group on position three once again. And now we have our fennel group and all the hide on positions one in six specific, respectively, below the ring instead. So these are our two possibilities for part B specifically. But otherwise we are done with this question. So, what we did just now was that we demonstrated how um deals all the reactions produce six member rings in a concerted mechanism. So, thanks for watching. And I hope you found this helpful

Predict the products of the following Diels–Alder reactions.
(c)
(d)

Key Concepts

Diels–Alder Reaction

Conjugated Dienes

Dienophile

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