00:01
Okay, this problem is having to start out with a 1 -3 cyclohexane diome, which is just a cyclohexane with a carbonio in the 1 in 3 position, and then we're supposed to transform that into a wyland my shear ketone, which is almost the same thing, except we have the extension of my carbon chain.
00:17
So ketone there, alken there, and methyl group there.
00:20
Okay, so looking at this, looking at my starting material, and looking at my ending product, it looks like i have undergone a lot of transformations, right? it looks like this is probably going to be a multi -step synthesis.
00:29
But in reality, i'm i can just break this up into its different components, and it would turn out to be something that we've learned in this chapter, because i see that i have the presence of an alpha beta unsaturated system.
00:39
And i know that in order to make alpha beta unsaturated systems like that, my molecule would have had to undergo an alval condensation.
00:45
So i know that this is eventually going to undergo an alva condensation reaction.
00:49
And i also see that i have extended my carbon chain, because i have six right here, and then i ended up with the addition of approximately five.
00:57
Okay, so i added five carbons to it.
00:59
So how do i do this? well, let's figure it out.
01:02
If i added carbons to it and i ended up with an alpha beta unsaturated system, then i would have probably undergone a robinson annulation.
01:09
And that's exactly what's going to happen here.
01:11
So a robinson annulation is a michael edition followed by an aldo connoisseation.
01:16
So what is the first reaction of a michael edition? well, first up, all we have to do is use a base.
01:21
So using sodium hydroxide.
01:24
My sodium hydroxide is going to deprotinate the most acidic hydrogen on this molecule.
01:28
So my most acidic hydrogen is the alpha carbon.
01:31
Which has the alpha hydrogen.
01:33
And that is the most acidic because it is sandwiched between this carbonyl and this carbonyl, right? because i also have alpha carbons on this side and this side, but this proton is sandwiched between both of them.
01:43
So it's extra acidic.
01:45
Okay, so noting that i'm going to deprotonate my acidic hydrogen, moving the electrons onto that carbon.
01:50
Okay, and then i should end up with the following, which i have my carbonyl, carbonil, and then lone pairs in that position.
01:56
Okay, so this is where things might get a little interesting because we might not know where to begin.
02:01
So we don't even know how to put carbons onto it to eventually make this product.
02:05
So this is where i would recommend working completely backwards.
02:08
Because i recognize that i have undergone an elbow condensation and i have undergone a michael edition, but i don't know where to go next from here.
02:16
So don't be afraid to work backwards if you don't know how to continue your forward synthesis.
02:21
Okay, so looking at this, let's work completely backwards.
02:24
Okay, so i'm going to draw my retro synthesis arrow.
02:28
Okay, so if i underwent an al -dol condensation, i know that i would have had to originate from an alcohol being there instead of my al -keen.
02:37
Because for aldol additions, we just eliminate my proton, we eliminate my alcohol to get an al -keen.
02:44
Okay, is that a five -carbon compound? i don't think so.
02:47
Let's draw one more carbon.
02:49
Okay, now we have my methyl group.
02:52
We have my carbonyl here.
02:54
And then, right, we have an al -keen here.
02:56
That al -keen was not always there.
02:57
It had to originate from the elimination of my alcohol.
03:01
So right here i have my alcohol.
03:03
And then as far as the forward synthesis goes, if i have a proton here, my sodium hydroxide is going to come in and deprotonate the hydrogen, moving the electrons onto this bond, and kicking out my alcohol.
03:14
So that's the mechanism for the forest synthesis, but obviously we don't have to show that for this.
03:19
Okay, so that is that.
03:21
And the alcohol is not always there either, right? it came about from something else.
03:25
So i'm going to continue this.
03:27
So how did this alcohol come there? was it originally a nucleophile and it just came in and attacked that carbon? no.
03:35
Because we know a little bit about all the condescations, we know that that originated from just an o -minus, in which we had an oxygen with a minus charge.
03:42
So same thing, except we just had o -minus.
03:48
Okay, so what next? well, that o -minus, same thing as the alcohol, it didn't just come there.
03:53
It didn't just originate as an o -minus, maybe o2 -minus, and then come in and attack that carbon...