SunriseSunset
Hazard to Self
Posts: 82
Registered: 9-6-2015
Location: USA
Member Is Offline
Mood: No Mood
|
|
aldehyde conversion to ketone or propene question
Is it possible to convert a molecule with a 2-methylpropanal to a ketone or propene, that correspond to the following structures?
I uploaded an attachment to help explain what I'm talking about. It seems like a brain blender sort of problem, but I figured to ask.
Are any of these things possible?
[Edited on 27-12-2015 by SunriseSunset]
|
|
|
zed
International Hazard
Posts: 2278
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
Member Is Offline
Mood: Semi-repentant Sith Lord
|
|
Looks like kind of an exotic starting material. Wouldn't you just prefer to purchase some Eugenol? AKA clove oil. From there you can easily make
either of the other two materials.
https://en.wikipedia.org/wiki/Eugenol
Available cheaper no doubt. http://www.ebay.com/itm/EUGENOL-1X4oz-Bottle-Dental-/2708645...
[Edited on 28-12-2015 by zed]
[Edited on 28-12-2015 by zed]
|
|
|
SunriseSunset
Hazard to Self
Posts: 82
Registered: 9-6-2015
Location: USA
Member Is Offline
Mood: No Mood
|
|
Thanks zed, but i'm just seeing if this could possibly work out in theory. I wouldn't dare waste such a material unless there was a sure route with
plenty of experimental data. lol I'm conservative :p
Btw, I'm not concerned about the stereo chemistry. just only the bonds.
Here's an idea, what if FIRST oxidize the aldehyde to a carboxylic acid, and then decarboxylate it? That might get
it partially the way there! to the shorter-chain alkane. :|
Then brominate the alkane with N-Bromosuccinimide, then use a strong base to yield the desired phenyl-1-propene
Or the phenylpropane could be oxidized to a secondary alcohol, then to the ketone desired. Not sure.
[Edited on 28-12-2015 by SunriseSunset]
|
|
|
CuReUS
National Hazard
Posts: 928
Registered: 9-9-2014
Member Is Offline
Mood: No Mood
|
|
there is a rearrangement to convert
2-phenylpropanal to phenylacetone using conc H2SO4 or HgCl2 given in strike's book " total synthesis 2 ", pg 186
(but it might not work for your compound,maybe the benzene ring needs to be alpha to the CHO for the rearrangement to work ? )
see this(for procedure)
http://www.sciencemadness.org/talk/viewthread.php?tid=19505
also see this
http://chemistry.mdma.ch/hiveboard/methods/000456276.html
carbonyls can be converted to alkenes with this reaction
http://www.sciencemadness.org/talk/viewthread.php?tid=64659#...
[Edited on 28-12-2015 by CuReUS]
|
|
|
MeshPL
Hazard to Others
Posts: 329
Registered: 20-4-2015
Location: Universe
Member Is Offline
Mood: No Mood
|
|
Here is a somewhat suitable conversion, not sure if reagents will fit your abilities:
1. Oxidise aldehyde to carboxylic acid. Choose mild oxidising agent, one that will not oxidise phenols, or benzylic carbons.
2. Decarboxylate carboxylic acid using Kochi reaction or Hunsdiecker reaction.
3a,b. Halogenated hydrocarbon with halogen atom in place of aldehyde group is your product. Now you can turn that into internal/external alkene mix by
elimination or alcohol by nucleophilic substitution with base. Whichever you choose, you will need to select good reagents and reaction conditions,
otherwise you will get a mixture of products. If you choose elimination, you will get a mixture of internal, external alkenes anyway. (I guess
~70%/30% each).
3c. External alkene can be main product of Hofmann elimination and Cope elimination, you will first need to convert your halocarbon to quatenary
ammonium hydroxide or tertiary amine oxide. Than you heat it/pyrolyse it. Yield of external alkene compared to internal can be good although there are
extra steps involved.
| Quote: |
Here's an idea, what if FIRST oxidize the aldehyde to a carboxylic acid, and then decarboxylate it? That might get it partially the way there! to the
shorter-chain alkane. :|
Then brominate the alkane with N-Bromosuccinimide, then use a strong base to yield the desired phenyl-1-propene.
|
Good idea, although N-Bromosuccinimide is not required, I think. Just bromine will quite selectively attack benzylic position. N-Bromosuccinimide is
required for situations where double bonds are present, and could be attacked. Although, I'm not sure about overbromination by Br2 vs NBS.
[Edited on 28-12-2015 by MeshPL]
|
|
|
CuReUS
National Hazard
Posts: 928
Registered: 9-9-2014
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by MeshPL  |
| Quote: |
Here's an idea, what if FIRST oxidize the aldehyde to a carboxylic acid, and then decarboxylate it? That might get it partially the way there! to the
shorter-chain alkane. :|
Then brominate the alkane with N-Bromosuccinimide, then use a strong base to yield the desired phenyl-1-propene.
|
Good idea, although N-Bromosuccinimide is not required, I think. Just bromine will quite selectively attack benzylic position. N-Bromosuccinimide is
required for situations where double bonds are present, and could be attacked. Although, I'm not sure about overbromination by Br2 vs NBS.
|
The ring is quite activated,so ring bromination could be a significant side reaction using NBS or Br2
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
