|
I am in second semester O-Chem and need to know if this method of synthesis is correct. There is another way to synthesize the product using organocuprates, but I came up with this method and am unsure whether or not it is valid. Any help is appreciated. Thanks in advance.
edit: I need insta-responses from geniuses!! my exam is tomorrow :O
Edit #2: I emailed my teacher and he told me that this method works. So for those of you wondering (I doubt anybody cares/knows what the hell this even is), the solution I made is correct. Only changes should be that in the last step, the amine and acid catalyst are added together in the same step, not separated into steps 1) and 2). Also, because there is an additional step in this method compared to using organocuprates, the yield will be lower.
 
|
Are you sure that's the right screenshot?
|
Once you know enough you best start manufacturing LSD to better the world.
|
Ok, sorry, uploaded wrong image at first. Thanks reflex, the correct image is posted now.
|
I walked through the reaction... first thing to note is you drew your first carbonyl funny, the second carbon should go down not up (sorry, it just bothers me  ).
Second: why use PCC? It's a secondary carbon, and while you could use it, might as well oxidize the crap out of it and use chromic acid to make sure it's converting to the ketone. I suppose oxidizing the double bond might be an issue but chromic acid isn't going to do that if you use the Jones reagent (dilute chromic acid in acetone basically).
Other than that it looks fine, although I didn't really think about rearrangements too much (I suspect there aren't any and if there are, I'm not going to do all your work for you :p).
|
|
|
yo useless, i was waiting for you to post man, haha. I see you put organic chemistry as your favorite book, are you a chem major or what? what is your career goal?
To zer0das, I used PCC because I am trying to oxidize and stop it at the ketone. If I used jones, it would go to a carboxylic acid cuz jones is very strong (so it would cleave it I think). Not too sure on this, useLess, is this the right thinking?
|
oh goodness, just reminds me that after physics and bio, i gotta study for ochem. good Lord have mercy on my soul.
|
i cant believe im learning almost the EXACT same thing in first year honors chemistry
|
It's pretty blurry, but let me take a look.
It looks like your first step is a Grignard reaction, in which you're using RMgCL. You should probably break up the reaction into multiple steps to clarify that - the first one to insert the magnesium between the carbon and the Chlorine, the second to react it with the aldehyde. Also, if you can find a way to get rid of the chlorine and use bromine instead, I would say to go for it, just because it's a much better Grignard reagent, and grignard reactions suck when you're doing them in the lab.
Secondly, I'm not sure why you need trichloromethane and heat along with the PCC - what PCC is is a mild reduction agent that won't touch double bonds, instead will only reduce alcohols to ketones or aldehydes, and doesn't require any acid catalyst, like chromates. You can just write PCC there and it will do the same job.
Your last step looks good, though I can't for the life of me remember the mechanism used for it. I should probably look that up.
Let me draw up an image of how I would write it.
Edit:
|
The Jones reagent is by definition mild chromic acid, so it wouldn't oxidize the double bond. PCC would work yeah, but waste issues aside, chromic acid would probably result in a higher yield. Not that that really matters for problems like this but EH.
And yeah, I was going to mention splitting the Grignard step off on its own, because anyone's gut reaction seeing a grignard with water is yuck. :p
|
Nice responses everyone. The way my teacher writes it in synthesis problems for the Grignard is the way I have it written (it's shorter that way anyway). If I were to write it out more formally though, I would show the steps separately.
For the PCC with CHCl3 and heat, that is just the way we learned it. The CHCl3 is the solvent and heat drives the reaction quickly.
To Plutonium, the mechanism involves using the mnemonic PADPED (if you learned that). Basically, you protonate the ketone, then perform addition, deprotonation, protonation, elimination, and deprotonation in a six step mechanism (it was on the test today).
Anyway, its nice to have people to discuss o-chem with. Most people despise the subject, but it is kind of interesting especially understanding how so many of these processes are used in metabolism of sugars and fats and so on. Thanks for the help guys, I really appreciate it.
|
|
|
|
|
|
EPT![[image loading]](http://i207.photobucket.com/albums/bb245/icydude21/o-chemproblem.jpg)
![[image loading]](http://i2.photobucket.com/albums/y32/gkclarkson/chem.jpg)
