03-05-02 20:39
No 277549
Are there any other catalysts for the Wacker Oxygenation of an alkene than Palladium? I have UTFSE here and abroad, and found not one thing.
Is there any other catalyst that will transform an olefin into a carbonyl??
I have been wondering about hydrogenation catalysts. I admit to totally 100% pullingnthis one out of my ass with no references whatsoever, and for that Im sorry, but I have read that most hydrogenation reactions are equilibrium reactions, influenced in the "right" direction by flooding the system with hydrogen. If this is so, then are these hydrogenation catalysts just reaction catalysts for the system?
Could they be used as oxygenation catalysts as well?
PrimoPyro
Vivent Longtemps La Ruche!
(Old P2P Cook)
03-05-02 22:38
No 277618
Is there any other catalyst that will transform an olefin into a carbonyl??
Osmium and vanadium can be used to produce glycols or epoxides.
(Distinctive Doe)
03-05-02 23:28
No 277667
Damn
I typed up a long answer but my computer burped and its gone.
PP
What is your goal? To use a transition metal catalyst or to get a ketone?
By definition it is not a real "Wacker" oxidation unless you use palladium.
Other Stuff
Electrode-Assisted Wacker Process
http://www.kcsnet.or.kr/publi/bul/bu01n5
Make a Difference Donate Now!! (http://www.lp.org/drugwar/)
(Hive Bee)
03-07-02 23:28
No 278800
PrimoPyro,
I am not aware of a Wacker oxidation that used anything other than Palladium. But I have seen "Wacker type" oxidations of olefins that used Pd0, like Pd(PPh3)4 and Hydrogen Peroxide or Oxone.
You have to understand the catalyis cycle. There are three main steps, and in a wacker oxidation they are Oxidative addition of the alkene to the metal, transmetalation where an -OH attachted to the metal center is coupled with the alkene, and reductive elimination where you lose the ketone and a water and end up with Pd0. This is then re-oxidized by CuIICl2. At two points during the catalysis cycle where you add a -OH or H2O to the metal, you lose a molecule of HCl, which in turn re-oxdises the Cu0.
The addition and elimination are the rate determining steps. Pd0 usually forms 4 coordinate complexes, and PdII 5 coordinate. If that is you were to attach a bridged diphosphine ligand, that would narrow the cone angle and favor the reductive elimination step. This could be accomplished by first making PdIICl2(MeCN)2. You would deprotonate Acetonitrile with LDA, and react it with PdIICl2. Then add 1/2 eq. of your diphosphine to get your four coordinate PalladiumII diphosphino dichloride. You can play with the cone angles by using different phosphines.
Oxidations can are done with other metals of course. My recommendation is to get a good book on Organometallic catalysts in organic synthesis, and find access to a database like CAS Scifinder or Beilstein Crossfire.
(Her Majesty, Stoni's Kitty)
03-08-02 14:37
No 279102
Rhodium chloride provides a catalyst that can be used in a Wacker analogue reaction. The mechanism is different but the results and experimental conditions are virtually the same.
Look it up in that cool book you should be getting in the mail soon.
(Master Searcher)
03-08-02 18:16
No 279199
You're not looking hard enough.
Patent US2701813
Patent US2071395
http://www.geocities.com/dritte123/Miscp
http://www.geocities.com/dritte123/PSPF.
(Hive Prodigy)
03-09-02 10:26
No 279597
Actually, I think I am. Although I appreciate those articles, they are not what I am talking about.
By the term "Wacker-like oxygenation" I imply oxidizing an alkene to a ketone in one step with a catalyst. To utilize those reactions, I would produce glycols, which would have to be rearranged to ketones. This is precisely what I wish to avoid.
foxy: Both. To use a less expensive catalyst than palladium to go straight from alkene to ketone.
PrimoPyro
Vivent Longtemps La Ruche!
(Master Searcher)
03-09-02 11:25
No 279628
Nickel chloride.
http://www.geocities.com/dritte123/PSPF.
(Hive Prodigy)
03-09-02 11:37
No 279634
Sir PolytheneSam: Those two words mean more to me than anything I've read in quite some time!
1.Will Nickel Chloride act in a similar manner to Palladium Chloride, producing a ketone from the alkene?
2.Is this discussed in your patents cited? I must have missed it if it was.
This is amazing if it truly works.
PrimoPyro
Vivent Longtemps La Ruche!
(Master Searcher)
03-09-02 11:48
No 279644
I read it in a patent somewhere, but I don't remember the number. It was just in one sentence which gave examples of possible catalysts. It might not provide high yields otherwise it would have been used by now. I'll look at the stack of patent notes I have. It might be in one of the lists.
http://www.geocities.com/dritte123/PSPF.
(Her Majesty, Stoni's Kitty)
03-09-02 11:54
No 279648
I could swear that I've seen manganese acetate or some other similar catalyst used to effect alkene conversion directly. This wasn't very developed in the one article that I read. But maybe in the last few years there has been more progress.
Also, there's the mercuric acetate/chromic acid oxidation of alkenes to ketones that is a direct analogue of the wacker as well. This is explained in detail in Strike's book.
All of these oxidations that you looking for are listed in the textbook you'll be receiving soon. Look in the back under "ketones" (heading, not index) and read the subsection "oxidation by noble metal catalyst salts" or something like that. I sure in ten years, there have been some tremendous advances in the art.
Good luck.
(Hive Prodigy)
03-09-02 11:58
No 279651
I wish it would hurry up and get here already. Ive been waiting anxiously for too long. My interest in catalysis grows...
I think Im going to buy that book on Catalysis that Wiley was promoting. It looked pretty in depth.
PrimoPyro
Vivent Longtemps La Ruche!