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Topic: Borodin-Hunsdiecker reaction  (Read 15104 times)

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Offline HP

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Borodin-Hunsdiecker reaction
« on: December 25, 2005, 03:05:40 PM »
Merry Christmas!

Today when i was listening my favourite opera Borodin's "Prince Igor" i remembered this man was professional chemist and amatheur composer as well..So on chemistry sound: The well-known Hunsdiecker reaction is when silver(I) salts of carboxylic acids react with halogens to give unstable intermediates which readily decarboxylate thermally to yield alkyl halides. R-COO:Ag + Br2--> R-Br + AgBr
First Borodin has performed this reaction obtaining alkyl fluorides. Can someone tell me what kind of reagents he has used do that and why name this reaction is much known as only Hunsdiecker one ?  ::)
HP
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Offline Albert

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Re:Borodin-Hunsdiecker reaction
« Reply #1 on: December 25, 2005, 04:54:24 PM »
He synthesized benzoyl fluoride, in Italy, in 1862.

That's it, for the moment, but I promise you I'll try to find more information.

Offline HP

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Re:Borodin-Hunsdiecker reaction
« Reply #2 on: December 26, 2005, 03:38:26 AM »
The information i could find is that he has tried reaction Ag-acetate with Br2 to yeld ethyl bromide: classical "Hunsdiecker"  reaction. But on one place on google it write he has obtained alkylfluorides by the same reaction but nothing write about the source of F he has used and i think its a mistake or speculation information. Yes later in his visit at Itally he has worked obtaining benzylfluoride by reaction benzylchloride(nasty smel) with the new reagent: acidic potasium fluoride - KHF2. He described the obtained oily substance(benzylfluoride) as much nasty smelling substance :'(
My tought is do you think its possible some reaction between Ag-salt carboxylic acids with this interesting KHF2? You know the story for discovering the element fluorine F2 when  Henry Moissan electrolyze KHF2. Sorry for the historical diversion:)
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Offline Albert

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Re:Borodin-Hunsdiecker reaction
« Reply #3 on: December 26, 2005, 06:57:35 AM »
do you think its possible some reaction between Ag-salt carboxylic acids with this interesting KHF2?

Well, I don't see nothing against it, as well as for what concerns HF, F2 or a fluoridating agent (even if I must admit I don't know whether they were already known or not).

He could have used KHF2 because it used it also to yield benzoyl fluoride, so I daresay he was quite prone to use it.

Offline HP

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Re:Borodin-Hunsdiecker reaction
« Reply #4 on: December 26, 2005, 07:28:09 AM »
Aha but i doubt KHF2 could fluorinate RCOO:Ag to
R-F.
Theres interesting variant this reaction with using combination KBr or KJ/H2O2 for halogenation. I am almost  sure that KF or KHF2 wouldnt work that but havent tried ;)
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Offline AWK

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Re:Borodin-Hunsdiecker reaction
« Reply #5 on: December 27, 2005, 05:16:43 AM »
The first paper on this reaction:
Borodin A. Annalen drr Chemie 1861, vol 119 page 121

Hunsdieckers published their paper in 1942 (Ber.75, 291 (1942))
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Offline HP

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Re:Borodin-Hunsdiecker reaction
« Reply #6 on: December 27, 2005, 12:00:09 PM »
Really interesting..81 years later :o is Hunsdieckers work plagiastic one? Or theres some new experimental facts in theirs publication?
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Offline AWK

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Re:Borodin-Hunsdiecker reaction
« Reply #7 on: December 29, 2005, 04:15:44 AM »
I read both original papers this morning.
Borodin discovered this reaction with silver acetate and bromine.
Hunsdieckers investigated this reaction using various salts of different acids and bromine also.

Borodin was a very interesting person, se: http://en.wikipedia.org/wiki/Borodin
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Offline HP

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Re:Borodin-Hunsdiecker reaction
« Reply #8 on: December 29, 2005, 12:31:46 PM »
Yes, Alexander Borodin was a genius both in science and music man of creativity. And the times he has lived were romantic times at the beginning organic chemistry:) And now my general apell for right naming this reaction as Borodin-Hunsdiecker- not Hunsdiecker, nor Hunsdiecker-Borodin;) In the name of Borodins bright memory...
By the way tell me please for my relieve if Hunsdieckers has reffered the work of Borodin in their own work.
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Offline AWK

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Re:Borodin-Hunsdiecker reaction
« Reply #9 on: December 30, 2005, 01:12:43 AM »
Quote
By the way tell me please for my relieve if Hunsdieckers has reffered the work of Borodin in their own work.
Yes, they did it.
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Offline HP

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Re:Borodin-Hunsdiecker reaction
« Reply #10 on: December 30, 2005, 11:36:31 AM »
Nice  :)
Now continue asking:
The sugested mechanism this reaction is radical chain mechanism as follows:
R-COO:-Ag+  +  Br2--> R-COOBr + AgBr
RCOOBr very unstable intermediate and decompose:
R-COOBr--> R-COO. + Br.
R-COO. --> R. + CO2 (something similar as the Kolbe method electrolyzis R-COO:Na+)
R. + R-COOBr--> R-Br + R-COO.
My question is if possible recombination reactions like:
R. + R. --> R-R
R. + Br. --> R-Br (you'll say what method will prove the R or Br source at the end R-Br product :)
R. + R-COO. --> R-COOR  ???
Thank you for the help
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Offline AWK

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Re:Borodin-Hunsdiecker reaction
« Reply #11 on: January 02, 2006, 03:48:56 AM »
Start reading from:
Chem. Rev.; 1956; 56(2); 219-269
and
J. Org. Chem.; 1961; 26(12); 5231-5232
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Offline HP

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Re:Borodin-Hunsdiecker reaction
« Reply #12 on: January 02, 2006, 04:09:37 AM »
Happy New year 2006 AWK!
Theres something wrong or not deep investigated in the sugested mechanism in literature i read on net - on first sight hope my sight alredy clear after 3 days parties ;D
Many side reactions possible if really radical mechanism i think  ???
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Offline AWK

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Re:Borodin-Hunsdiecker reaction
« Reply #13 on: January 03, 2006, 02:08:08 AM »
Radicals are always highly energetic, hence side reactions are always possible.
Investigators very often show only  the way to the main product, though in Borodin-Hunsdiecker reaction yield is moderate to ~80 %.
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Offline HP

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Re:Borodin-Hunsdiecker reaction
« Reply #14 on: January 03, 2006, 11:14:02 AM »
Thank you for the help AWK! I was about sure for the possible side reactions occur. 80% main product yeld, hm not so bad but do you think theres some yeld limit determined by the reaction mechanism: i mean  theres reaction RCOOBr + R. comming also from RCOOH i am owfully bad in math but theres something strange on first sight :)
xpp

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